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  • gene expression  (314)
  • Springer  (314)
  • Blackwell Publishing Ltd
  • 1995-1999  (307)
  • 1980-1984  (7)
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  • 1925-1929
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 52 (1996), S. 942-949 
    ISSN: 1420-9071
    Keywords: Apoptosis ; transglutaminase ; signalling ; gene expression ; promoter elements ; retinoic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Clarification of the molecular details of forms of natural cell death, including apoptosis, has become one of the most challenging issues of contemporary biomedical sciences. One of the effector elements of various cell death pathways is the covalent cross-linking of cellular proteins by transglutaminases. This review will discuss the accumulating data related to the induction and regulation of these enzymes, particularly of tissue type transglutaminase, in the molecular program of cell death. A wide range of signalling pathways can lead to the parallel induction of apoptosis and transglutaminase, providing a handle for better understanding the exact molecular interactions responsible for the mechanism of regulated cell death.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 51 (1995), S. 1116-1123 
    ISSN: 1420-9071
    Keywords: Antisense RNA ; gene expression ; insertional mutagenesis ; physical mapping ; reporter genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Over the past ten years, powerful molecular genetic techniques have been developed to analyze gene function inDictyostelium. DNA-mediated transformation using a variety of selections and vectors has allowed the introduction of wild-type or modified genes that are under various forms of transcriptional control. Homologous recombination is efficient and can be used to modify the genome in precise ways. In addition, it is now possible to clone genes based on their mutant phenotype alone, either by insertional mutagenesis, or by screening antisense expression cDNA libraries. Finally, a nearly complete physical map of the genome is available and so genes are easily mapped by physical techniques. We discuss many of these advances within the context of major research problems presently under study.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 51 (1995), S. 606-611 
    ISSN: 1420-9071
    Keywords: Metallothionein ; isometallothioneins ; gene expression ; rabbit kidney cell-line ; cadmium adaptation ; zinc adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We explored the molecular genetics underlying the massive induction of isoMTs by Zn2+ or Cd2+ in metal tolerant rabbit kidney (RK-13) sub-line cells, using band shift assays and Southern blotting analysis. In sub-line cells accommodated to intermediate metal concentrations (100 μM Zn2+; 1–20 μM Cd2+) evidence suggested that the increase in the capacity for isoMT synthesis is brought about by an increased binding activity of the nuclear transcription factors MTF-1 and Sp1. Using quantitative band shift analysis with a mouse MRE-d oligonucleotide probe, the binding of both transcription factors was found to be enhanced two to three times over the binding activity measured in the unexposed parental RK-13 cells. Their increase in binding activity is probably the cause of the overexpression of MT genes and the development of metal tolerance in these cells. In cells tolerant to the highest concentrations of metal the analysis of Southern blot signals revealed MT gene amplification to be the most probable cause of the increased MT production. Thus, in cells of sub-lines growing in the presence of 350 μM Zn2+, two of the isoMT genes were coordinately triplicated and in cells tolerant to 150 μM Cd2+ one isoMT gene was amplified two-fold.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 11 (1998), S. 345-358 
    ISSN: 1572-8773
    Keywords: calcium ; CREB ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Through the evolution of multicellular organisms, calcium has emerged as the preferred ion for intracel-lular signalling. It now occupies a pivotal role in many cell types and nowhere is it more important than in neurons, where it mediates both the relaying and long-term storage of information. The latter is a process that enables learning and memory to be formed and requires the activation of gene expression by calcium signals. Evidence from a number of diverse organisms shows that transcription mediated by the transcrip-tion factor CREB is critical for learning and memory. Here we review the features of CREB activation by calcium signals in mammalian cells. In contrast to other transcription factors, its regulation is dependent on an elevation of nuclear calcium concentration, potentially placing this spatially distinct pool of calcium as an important mediator of information storage.© Kluwer Academic Publishers
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology reporter 16 (1998), S. 323-339 
    ISSN: 1572-9818
    Keywords: Aux/IAA genes ; gene expression ; gene families ; RT-PCR ; tomato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have developed an improved method for determination of gene expression levels with RT-PCR. The procedure is rapid and does not require extensive optimization or densitometric analysis. Since the detection of individual transcripts is PCR-based, small amounts of tissue samples are sufficient for the analysis of expression patterns in large gene families. Using this method, we were able to rapidly screen nine members of the Aux/IAA family of auxin- responsive genes and identify those genes which vary in message abundance in a tissue- and light-specific manner. While not offering the accuracy of conventional semi-quantitative or competitive RT-PCR, our method allows quick screening of large numbers of genes in a wide range of RNA samples with just a thermal cycler and standard gel analysis equipment.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology reporter 17 (1999), S. 371-383 
    ISSN: 1572-9818
    Keywords: epidermal peel ; extraction ; gene expression ; stomata ; tree tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stomatal guard cells are critical for maintenance of plant homeostasis and represent an interesting cell type for studies of leaf cell differentiation and patterning. Here we describe techniques for the isolation of guard cell RNA and protein from blended epidermal peels of Nicotiana glauca. The RNA isolation procedure is a modification of the hot borate method, which is particularly well-suited for recalcitrant tissues. Protein was extracted by disrupting guard cell-enriched epidermis with a French® press. This system offers the following advantages: relatively high yield, low or no contamination by other cell types, fresh tissue as a source of RNA and protein rather than protoplasts, and a plant species that is readily transformable. These techniques will allow for cloning and analysis of genes expressed in guard cells, application of traditional biochemical techniques to guard cell proteins, as well as characterization of genetic manipulation of guard cell function in transgenic plants.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 52 (1996), S. 888-891 
    ISSN: 1420-9071
    Keywords: Ageing ; rat ; brain ; gene expression ; differential display
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have used the polymerase chain reaction (PCR)-based technique of differential display to analyse changes in gene expression during ageing of the rat brain. In this approach we have compared three young adult (6 months) with three old adult (20 months) animals. RNA preparations from the homogenised brains were subjected to reverse transcriptase (RT)-PCR using 36 different combinations of primer pairs. Any PCR product which was consistently found to be more prominent in the three young brains compared to the three old brains, and vice versa, was scored as potentially representing a gene which was differentially expressed during the ageing of this tissue. Out of a possible 2000+PCR products we identified 44 that might represent genes that exhibit differential expression during ageing of the rat brain. An initial screen of these fragments, by Southern-blotting the PCR products and hybridising them with cDNA probes derived from either young or old brain RNA preparations, indicated that 40% of them represented genes that were differentially expressed. This approach is likely to prove invaluable for identifying cohorts of genes that show differential expression during the ageing process.
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  • 8
    ISSN: 1432-203X
    Keywords: glyphosate ; gene expression ; gene amplification ; cell culture ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The stability and expression of amplified 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) genes was examined in glyphosate resistant tobacco cells grown in glyphosate-free medium, and in plantlets regenerated from resistant cells. Amplified DNA was maintained in resistant cells grown in the absence of glyphosate for three years. Amplified EPSPS genes were retained in regenerated plantlets at levels comparable to those observed in the resistant cells, and EPSPS mRNA was overexpressed (compared to unselected plantlets). However, glyphosate resistance in cell lines grown in glyphosate-free medium declined 7-fold, and in regenerated plantlets approximately 20-fold, compared to resistant cells maintained under glyphosate selection. In plantlets, reduced resistance correlated with lower levels of EPSPS mRNA. Plantlets regenerated from resistant cells exhibited morphological variation, and had an approximate doubling of their nuclear genome size.
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  • 9
    ISSN: 1573-4919
    Keywords: vasoactive intestinal peptide ; ulcerative colitis ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The availability of colon provides a ready source of human neurons. Among the products of nerve cell bodies, vasoactive intestinal peptide is a neuropeptide that serves as a marker of non-adrenergic, non-cholinergic inhibitory nerves in colon. These nerves have been proposed to be involved in regulation of immune function, secretion, and smooth muscle function. In previous work, we identified decreased tissue levels of vasoactive intestinal peptide in a disorder of chronic colonic mucosal inflammation, ulcerative colitis. We hypothesized that diminished gene expression of vasoactive intestinal peptide could result in decreased tissue levels of this neuropeptide. Sigmoid colon was obtained at surgery from controls (n=6) and patients with ulcerative colitis (n=6). Vasoactive intestinal peptide mRNA was quantified by Northern blot hybridization and tissue levels of vasoactive intestinal peptide were determined by radioimmunoassay. Tissue vasoactive intestinal peptide was decreased only in the mucosalsubmucosal layer of ulcerative colitis (p=.02). There was a single 1.7 kbase vasoactive intestinal peptide transcript identified in both control colon and ulcerative colitis. Normalized vasoactive intestinal peptide mRNA levels were increased by 260% in ulcerative colitis compared to controls (p〈.01). These observations suggest that decreased vasoactive intestinal peptide gene expression or abnormal post-transcriptional processing are not primary defects in this disorder of chronic inflammation. The findings support the alternative hypothesis that axonal degeneration in ulcerative colitis could result in increased expression of neuronal vasoactive intestinal peptide mRNA.
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  • 10
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; insulin ; calcium ; gene expression ; rat liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of refeeding on the expression of Ca2+-binding protein regucalcin mRNA in the liver of fasted rats was investigated. When rats were fasted overnight, the hepatic regucalcin mRNA level was reduced about 70% of that in feeding rats. Refeeding produced a remarkable elevation of hepatic regucalcin mRNA level (about 150–170% of fasted rats). Liver regucalcin concentration was appreciably increased by refeeding, although it was not altered by fasting. The oral administration of glucose (2 g/kg body weight) to fasted rats caused a significant increase in hepatic regucalcin mRNA level. Moreover, hepatic regucalcin mRNA level was clearly elevated by a single subcutaneous administration of insulin (10 and 100 U/kg) to fasted rats. The hormonal effect was not further enhanced by the simultaneous administration of calcium chloride (250 mg Ca/kg) to fasted rats, although calcium administration stimulated regucalcin mRNA expression in the liver. The present study suggests that the expression of hepatic regucalcin mRNA stimulated by refeeding is significantly involved in the action of insulin and/or calcium as stimulating factors.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 143 (1995), S. 67-71 
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; gene distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The existence and expression of gene encoding the Ca2+-binding protein regucalcin in various species and tissues were investigated with Southern and Northern hybridization analyses using regucalcin cDNA (0.9 kb of open reading frame). Genomic Southern hybridization analysis demonstrated that regucalcin gene was widely conserved among higher animals including human, monkey, rat, mouse, dog, bovine, rabbit and chicken. The gene was not found in yeast. The Northern blot analysis of poly (A)+RNAs extracted from the liver of various species showed that regucalcin mRNA was predominantly expressed in rat and mouse, although the expression was also seen in human, bovine and chicken. Furthermore, the enzyme-linked immunoadsorbent assay (ELISA) with rabbit-anti-regucalcin IgG indicated that hepatic regucalcin concentration was most pronounced in rat as compared with that of guinea pig, mouse and chicken. These observations show that the gene expression of regucalcin and its protein synthesis is unique in the liver of rats, suggesting the existence of a specific mechanism in demonstrating regucalcin synthesis from gene.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 143 (1995), S. 137-141 
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; estrogen ; gene expression ; rat liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of nuclear receptor-related hormones on the expression of hepatic calcium-binding protein regucalcin mRNA in rats was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin cDNA (0.9 kb of open-reading frame). A single subcutaneons administration of 17β-estradiol (0.5, 1.0 and 2.0 mg/kg body weight) in rats induced a remarkable increase of regucalcin mRNA in liver; the level was about 200% of control at 24 h after the administration of 2.0 mg/kg. The increase showed about 350% even at 6 h after the administration. Meanwhile, hepatic regucalcin mRNA level was not appreciably altered by a single subcutaneous administration of thyroxine (T4) (20, 40 and 80 mg/kg) or hydrocortisone (10 and 30 mg/kg) in rats. The present study demonstrates that the expression of hepatic regucalcin mRNA is stimulated by estrogen action in the liver nuclei of rats.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 144 (1995), S. 105-108 
    ISSN: 1573-4919
    Keywords: fatty acid synthase ; gene expression ; and thyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of triiodothyronine (T3) on regulation of fatty acid synthase in chicken liver was investigated. In hypothyroid animals, enzyme activity was about one half of that in euthyroid animals. T3 treatment increased the enzyme activity in hypothyroid animals. There is little difference in both the mRNA concentration and the transcription rate between euthyroid and hypothyroid animals. T3 treatment markedly decreased both the mRNA concentration and the transcription rate in euthyroid and hypothyroid animals. These results suggested that T3 maintained the normal level of enzyme expression primarily by stimulating the post-transcriptional step, while the transcription of the gene was inhibited by hyperthyroidism.
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  • 14
    Electronic Resource
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    Springer
    Molecular and cellular biochemistry 155 (1996), S. 85-90 
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; rat hepatoma ; Morris hepatoma cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Whether the gene expression of hepatic Ca2+-binding protein regucalcin is altered in hepatomas was investigated. The change in regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin complementary DNA (0.9 kb). Rat hepatoma was induced by continuous feeding of basal diet containing 0.06% 3′-methyl-4-dimethylaminoazobenzene (3′-Me-DAB). After 35 weeks feeding, rats were sacrificed, and the non-tumorous and tumorous tissues of the livers were removed. In individual rats, the regucalcin mRNA levels in the tumorous tissues were generally decreased in comparison with that of the non-tumorous tissues of the chemical-fed rats, although the chemical administration might decrease the mRNA expression in normal rat liver, suggesting that the chemical administration causes a suppresive effect on the mRNA expression. When the genomic DNA extracted from the liver tumorous tissues was digested with restriction enzymes (EcoRI, BamHI and HindIII) and analyzed by Southern blotting, no rear-ranged band was found in the regucalcin gene from the hepatoma. Interestingly, in the transplantable Morris hepatoma cells, the regucalcin mRNA was markedly expressed, while the albumin mRNA was expressed only slightly. The present study demonstrates that regucalcin mRNA is clearly expressed in the transformed cells (Morris hepatoma cells).
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  • 15
    Electronic Resource
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    Springer
    Molecular and cellular biochemistry 155 (1996), S. 105-111 
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; aldosterone ; estrogen ; dexamethasone ; gene expression ; rat kidney cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of various steroid hormones on the expression of calcium-binding protein regucalcin mRNA in the kidney cortex of rats was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using rat liver regucalcin complementary DNA (0.9 kb of open-reading frame). Regucalcin mRNA was expressed in the kidney cortex but not the medulla. Rats received a single subcutaneous administration of steroid; the animals were sacrificed 60 min after the treatment of aldosterone (2.5, 5.0 and 10 μg/100 g body weight) or 6 h after the treatment of estrogen (17β-estradiol; 0.05, 0.1 and 0.2 mg/100 g), hydrocortisone (0.5, 1.0 and 3.0 mg/100 g) and dexamethasone (50, 100 and 150 μg/100 g). Regucalcin mRNA levels in the kidney cortex were clearly diminished by the administration of aldosterone or estrogen, while hydrocortisone administration had no effect. The administration of dexamethasone (100 μg/100 g) caused a remarkable increase of regucalcin mRNA levels in the kidney cortex. The dexamethasone-induced increase in regucalcin mRNA levels was completely blocked by the simultaneous administration of cycloheximide (150 μg/100 g), although the drug administration had no effect on the mRNA levels in control rats. Meanwhile, the dexamethasone administration did not cause an appreciable alteration of calcium content in the kidney cortex. The present study demonstrates that, of the various steroid hormones used, dexamethasone uniquely has a stimulatory effect on regucalcin mRNA expression in the kidney cortex of rats. The steroid effect may be mediated through a newly synthesized protein.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 160-161 (1996), S. 307-313 
    ISSN: 1573-4919
    Keywords: myocardium ; hypertension ; gene expression ; estrogens ; cardiac hypertrophy ; signal transduction ; genetic program
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Gender specific differences in cardiovascular disease are largely mediated by sex hormones. The use of estrogens significantly reduces the overall incidence of heart disease in postmenopausal women. Beneficial effects of estrogens on plasma lipoprotein levels are clearly established. However, these do not explain the magnitude of risk reduction seen in clinical studies. Thus, additional and currently unknown functions of estrogens must be operative. Elucidation of the exact estrogen action in the heart will have important implications in the treatment of cardiovascular disease. It will probably enhance the therapeutic repertoire in treating heart disease, the most common cause of death in industrialized countries. We will review the current understanding of the function of estrogens in the heart and discuss potential strategies on how to apply these data to clinical practice.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 162 (1996), S. 139-144 
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; saline ingestion ; hypertensive rats ; kidney cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of adrenalectomy (ADX) or saline ingestion, which is a hypertensive factor, on the expression of calcium-binding protein regucalcin mRNA in the kidney cortex of rats was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using rat liver regucalcin complementary DNA (0.9 kb of open-reading frame). Regucalcin mRNA was expressed in the kidney cortex but not the medulla. Rats were adrenalectomized, and 48 h later they were sacrificed. ADX caused a reduction of regucalcin mRNA levels in the kidney cortex, suggesting that adrenal glands participate in the regulation of the mRNA expression. This reduction was not restored by the subcutaneous administration of dexamethasone with an effective dose (1 mg/kg body weight), which can stimulate kidney regucalcin mRNA expression. Regucalcin mRNA levels in the kidney cortex of rats were markedly suppressed by the ingestion of saline for 7 days. The ADX-induced decrease of renal cortex regucalcin mRNA levels was not appreciably restored by saline ingestion. Moreover, regucalcin mRNA levels in the kidney cortex of spontaneous hypertensive rats (SHR) were clearly decreased as compared with that of control (Wistar-Kyoto) rats. Meanwhile, calcium content in the kidney cortex was not significantly decreased by ADX or saline ingestion. The present study suggests that the expression of regucalcin mRNA in the kidney cortex of rats is suppressed by saline administration.
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  • 18
    ISSN: 1573-4919
    Keywords: calreticulin ; gene expression ; steroid receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Calreticulin is a ubiquitously expressed Ca2+ binding protein of the endoplasmic reticulum which inhibits DNA binding and transcriptional activation by steroid hormone receptors. In this study the effects of calreticulin on tyrosine aminotransferase (TAT) gene expression in cultured McA–RH7777 hepatocytes was investigated. McA–RH7777 cells were stably transfected with calreticulin expression vector to generate cells overexpressing the protein. The transcriptional activity of the TAT gene, which is glucocorticoid–sensitive and cAMP–dependent, was investigated in the mock transfected McA–RH7777 and in cells overexpressing calreticulin (designated McA–11 and McA–17). In the presence of dexamethasone or the cAMP analog (CTP–cAMP) expression of the TAT gene was induced in mock transfected McA–RH7777 cells by approximately 4.5 and 5 fold, respectively. In McA–11 and McA–17 cells, overexpressing calreticulin, glucocorticoi ever, the CTP–cAMP–dependent expression of the TAT gene was not affected. The ability of calreticulin to inhibit glucocorticoid–sensitive TAT gene expression but not the cAMP–dependent expression of the gene suggests that the protein affects specifically the action of transcription pathways involving steroid receptors or transcription factors containing KxFF(K/R)R–like motifs. Calreticulin may play an important role in the regulation of glucocorticoid–sensitive pathway of expression of the hepatocytes specific genes during development.
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  • 19
    Electronic Resource
    Electronic Resource
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    Molecular and cellular biochemistry 148 (1995), S. 45-57 
    ISSN: 1573-4919
    Keywords: manganese ; superoxide dismutase ; gene expression ; hyperoxide lung injury ; nuclear factor kappa B
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract TNFα and IL-1 each can activate NF-κB and induce gene expression of manganese superoxide dismutase (MnSOD), a mitochondrial matrix enzyme which can provide critical protection against hyperoxic lung injury. The regulation of MnSOD gene expression is not well understood. Since redox status can modulate NF-κB and potential κB site(s) exist in the MnSOD promoter, the effect of thiols (including NAC, DTT and 2-ME) on TNFα and IL-1 induced activation of NF-κB and MnSOD gene expression was investigated. Activation of NF-kB and increased MnSOD expression were potentiated by thiol reducing agents. In contrast, thiol oxidizing or alkylating agents inhibited both NF-κB activation and elevated MnSOD expression in response to TNFα or IL-1. Since protease inhibitors TPCK and TLCK can inhibit NF-κB activation, we also investigated the effect of these compounds on MnSOD expression and NF-κB activation. TPCK and TLCK each inhibited MnSOD gene expression and NF-κB activation. Since the MnSOD promoter also contains anAP-1 binding site, the effect of thiols and thiol modifying agents on AP-1 activation was investigated. Thiols had no consistent effect onAP-1 activation. Likewise, some of the thiol modifying compounds inhibited AP-1 activation by TNFα or IL-1, whereas others did not. Since diverse agents had similar effects on activation of NF-κB and MnSOD gene expression, we have demonstrated that activation of NF-κB and MnSOD gene expression are closely associated and that reduced sulfhydryl groups are required for cytokine mediation of both processes.
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  • 20
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; calmodulin ; spontaneous hypertensive rats ; rat kidney cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The expression of calcium-binding protein regucalcin mRNA in the kidney cortex of rats ingested with saline was investigated. The alteration in regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin complementary DNA (0.9 kb of open reading frame). Rats were freely given saline as drinking water for 7 days. Regucalcin mRNA levels in the kidney cortex were suppressed by saline ingestion. When calcium chloride (10 mg Ca/100 g body weight) was intraperitoneally administered to rats ingested with saline for 7 days, the effect of calcium administration to increase regucalcin mRNA levels was weakened by saline ingestion. Such effect was also seen by the administration of 2.5 and 5 mg Ca/100 g. Regucalcin mRNA levels in the kidney cortex of spontaneous hypertensive rats (SHR) were not appreciably increased by the administration of calcium (10 mg/100 g). Meanwhile, calcium content in the kidney cortex was significantly elevated by the administration of calcium (10 mg/100 g) to normal rats. This increase was weakened in saline-ingested rats. Moreover, Ca2+/calmodulin-dependent protein kinase activity in the cytosol of kidney cortex was significantly decreased by saline ingestion. These results suggest the possibility that saline ingestion-induced suppression of regucalcin mRNA expression in the kidney cortex is partly involved in the attenuation of Ca2+ signalling.
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  • 21
    ISSN: 1573-4919
    Keywords: microbodies ; diabetes mellitus ; steroid hormone receptor ; β-oxidation ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract To determine whether the increased fatty acid β-oxidation in the peroxisomes of diabetic rat liver is mediated by a common peroxisome proliferation mechanism, we measured the activation of long-chain (LC) and very long chain (VLC) fatty acids catalyzed by palmitoyl CoA ligase (PAL) and lignoceryl CoA ligase and oxidation of LC (palmitic acid) and VLC (lignoceric acid) fatty acids by isotopic methods. Immunoblot analysis of acyl-CoA oxidase (ACO), and Northern blot analysis of peroxisome proliferator-activated receptor (PPAR-α), ACO, and PAL were also performed. The PAL activity increased in peroxisomes and mitochondria from the liver of diabetic rats by 2.6-fold and 2.1-fold, respectively. The lignoceroyl-CoA ligase activity increased by 2.6-fold in diabetic peroxisomes. Palmitic acid oxidation increased in the diabetic peroxisomes and mitochondria by 2.5-fold and 2.7-fold, respectively, while lignoceric acid oxidation increased by 2.0-fold in the peroxisomes. Immunoreactive ACO protein increased by 2-fold in the diabetic group. The mRNA levels for PPAR-α, ACO and PAL increased 2.9-, 2.8- and 1.6-fold, respectively, in the diabetic group. These results suggest that the increased supply of fatty acids to liver in diabetic state stimulates the expression of PPAR-α and its target genes responsible for the metabolism of fatty acids.
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  • 22
    ISSN: 1573-4927
    Keywords: esterase ; duplication ; gene expression ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An esterase duplication is described in the sibling species pair Drosophila mojavensis and Drosophila arizonensis. We present evidence for two separate structural loci mapping at a distance of less than 0.16 recombination units from each other. Alleles at the two loci have the same substrate specificities and form small amounts of interlocus heterodimers. One locus (Est-5) is functioning throughout the insect's life cycle and appears at high concentrations in the hemolymph and the fat body. Its duplicate (Est-4) functions only during the late larval stage and is concentrated mainly in the carcass. No null alleles at either locus were observed in population surveys. An examination of 12 other species from the repleta group, to which D. mojavensis and D. arizonesis belong, suggests that Est-5 is universally present, but the activity levels of Est-4 vary among species and may be totally absent in some species. Variation in the level of Est-4 activity does not closely follow the phylogenetic relationship.
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  • 23
    ISSN: 1573-4927
    Keywords: evolution ; polyploidy ; ribosomal RNA ; protein synthesis ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Hidden breaks occur in the ribosomal RNA of tetraploid Cyprinid fish such that the large ribosomal RNA (28 S) yields upon denaturation two RNA fragments of 8.7×105 and 5.0×105 daltons, whereas the small rRNA (18 S) yields fragments of 3.2×105 to 5.0×104 daltons. In tetraploid Cyprinids hidden breaks occur only in the rRNA of somatic tissue and not in oocytes and sperm cells. Hidden breaks can be detected only slightly in diploid Cyprinid species. Ribosomes purified from somatic tissue of tetraploid Cyprinids show a reduced efficiency in protein synthesis in vitro. The ribosomal proteins from diploid and tetraploid Cyprinid fish show considerable electrophoretic differences. This is discussed in light of a possible functional role of hidden breaks in rRNA in the process of diploidization of gene expression in tetraploid Cyprinid species.
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    Molecular and cellular biochemistry 155 (1996), S. 153-162 
    ISSN: 1573-4919
    Keywords: apolipoprotein B and E ; lipid ; gene expression ; rat ; mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The aim of the present investigation was to study the regulation of apolipoprotein E by two dietary nutrients, saturated fat and cholesterol, known to raise plasma cholesterol levels. ApoE is a protein component of several classes of lipoproteins including VLDL and HDL, and dietary lipids may regulate VLDL and apoE-containing HDL particles through their effects on apoE gene. Male rats and mice were fed the following 4 diets: control diet (C); high cholesterol diet with 0.5% cholesterol (HC); high fat diet with 20% hydrogenated coconut oil (HF); and high fat plus high cholesterol diet with 0.5% cholesterol and 20% fat (HF/C). Plasma cholesterol levels remained unchanged on HC diet, but in mice VLDL-cholesterol increased by 31%. HF diet increased VLDL and LDL by 15–17% in rats, and 21% in mice. A combination of fat and cholesterol diet showed pronounced effects on plasma lipoprotein concentrations, raising apoB-containing particles by 21% and 44% in mice and rats, respectively. Plasma apoE levels increased significantly on all diets. The mechanism of regulation of increased plasma apoB and apoE levels was examined. Quantification of hepatic apoB mRNA showed a lack of correlation between plasma apoB and hepatic apoB mRNA levels, suggesting that posttranscriptional regulation increased plasma apoB-containing lipoproteins in animals fed saturated fat diets. Hepatic apoE mRNA levels increased significantly in animals fed cholesterol-rich diets. However, despite increased plasma apoE levels on diet containing only saturated fat, hepatic apoE mRNA did not change. Synthesis of apoE on the liver polysomes increased selectively on cholesterol-rich diets. These results suggest that cholesterol-rich diets altered apoE, in part, by transcriptional mechanism, and saturated fat-rich diets increased plasma apoE levels by posttranscriptional mechanism, possibly decreased receptor-mediated uptake of apoE-containing particles. The regulation of LDL receptor was also studied since plasma apoB and E levels may be altered by LDL receptor-mediated uptake by the hepatocytes. As expected, high cholesterol diet decreased LDL receptor mRNA by 30–40%. However, the LDL receptor protein on liver membranes did not change on any of the test diets in both animal species. Hepatic cholesterol content increased several fold selectively on high cholesterol diets. These findings suggest that: 1) both transcriptional and posttranscriptional mechanisms are important in regulating plasma apoB and E containing lipoproteins; 2) dietary cholesterol regulates apoE gene by a transcriptional mechanism anddietary saturated fat by posttranscriptional mechanism; and 3) changes in the hepatic apoE and LDL receptor mRNA are associated with the changes in intracellular cholesterol concentrations.
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    Molecular and cellular biochemistry 146 (1995), S. 71-77 
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; rat kidney cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The expression of calcium-binding protein regucalcin mRNA in the kidney cortex of rats was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin complementary DNA (0.9 kb of open-reading frame). Regucalcin mRNA was expressed in the kidney cortex, and this expression was clearly increased by a single intraperitoneal administration of calcium chloride solution (5–15 mg Ca/100 g body weight) in rats; this increase was remarkable at 60–120 min after the administration. Thyroparathyroidectomy (TPTX) caused a slight decrease of regucalcin mRNA levels in the kidney cortex. However, the administration of calcium (10 mg/100 g) in TPTX rats produced a clear increase of regucalcin mRNA levels in the kidney cortex. The subcutaneous administration of calcitonin (10–100 MRC mU/100 g) or parathyroid hormone [1–34] (1–10 U/100 g) in TPTX rats which received calcium (10 mg/100 g) administration did not cause an appreciable alteration of regucalcin mRNA levels in the kidney cortex, suggesting that the mRNA expression is not stimulated by calcium-regulating hormones. The administration of trifluoperazine (TFP; 5 mg/100 g), an inhibitor of Ca2+/calmodulin action, completely blocked the expression of regucalcin mRNA stimulated by calcium administration. Now, calcium content in the kidney cortex was significantly elevated by a single intraperitpneal administration of calcium (10 mg/100 g) in rats. The present study clearly demonstrates that the expression of regucalcin mRNA in the kidney cortex is stimulated by calcium administration in rats. This expression may be mediated through Ca2+/calmodulin action in the kidney cortex.
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  • 26
    ISSN: 1573-4919
    Keywords: fatty acid transport protein ; gene expression ; subtractive hybridization ; oxidative stress ; ischemia/reperfusion ; ischemic preconditioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract In this study, ischemia and oxidative stress-inducible gene expression in heart was examined by subtractive hybridization technique. Total RNA was isolated from ventricular muscle fragments of normal and oxidative stress-induced hearts. Poly (A)+ RNA was purified followed by the construction of a plasmid cDNA library. This was followed by the subtractive screening of oxidative stress-induced cDNA library. The positive colonies were amplified and the plasmid isolated. An aliquot was subjected to restriction cutting with Bam H1 and EcoRl; the fragments corresponding to cDNA insert were separated by electrophoresis, radiolabeled by random-primed DNA synthesis, and used as probes in standard Northern blotting experiments. An aliquot containing the plasmid from the confirmed positives was then subjected to bidirectional partial DNA sequencing (using M13 and T7/T3α primers) by the chain-extension/chain termination method. These sequences were subjected to a computerized search for homologies against all sequences in the updated worldwide Gen Bank and EMBL sequence databases followed by restriction mapping and reading frame identification. Out of 24 putative positive colonies screened, one clone was matched with 〉 97% homology with FAT gene that has been implicated in binding or transport of long chain fatty acids. cDNA probe synthesized from this clone identified two major transcripts of 4.8 and 2.9 kb. Additional experiments were then performed where isolated perfused rat hearts were subjected to the following treatments: (1) 5 min ischemia; (2) 10 min ischemia; (3) 20 min ischemia; (4) 5 min ischemia followed by 10 min reperfusion (ischemic preconditioning); and (5) 5 min ischemia followed by 10 min reperfusion, repeated four times (4 × preconditioning). RNAs were extracted from these hearts and hybridized with the FAT cDNA probe. The results indicated that FAT gene was induced by oxidative stress, ischemic preconditioning, but not by ischemia. (Mol Cell Biochem 160/161: 241–247, 1996)
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  • 27
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    Keywords: regucalcin ; calcium-binding protein ; gene expression ; diabetic state ; ethanol ; liver injury
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The alteration in calcium-binding protein regucalcin in the liver and serum of rats with streptozotocin (STZ)-diabetic state or ethanol ingestion was investigated. STZ (6.0 mg/100 g body weight) was subcutaneously administered in rats, and 1 or 3 weeks later they were sacrificed by bleeding. Liver regucalcin mRNA levels were not clearly altered by the diabetic state, as evidenced by Northern blotting using regucalcin cDNA (0.9 kb of open reading frame). Based on enzyme-linked immunoadsorbent assay (ELISA) with rabbit-anti-regucalcin IgG, hepatic regucalcin concentration was decreased about 50% of control levels by STZ treatment. However, serum regucalcin concentration was not significantly altered by STZ treatment. Meanwhile, when rats ingested ethanol (10 and 30%) in the drinking water for 2 weeks, liver regucalcin mRNA levels were clearly increased, although hepatic regucalcin concentration was significantly decreased. Serum regucalcin concentration was not appreciably altered. Serum transaminases (GOT and GPT) activities were significantly increased at 1 or 3 weeks after STZ administration in rats, while their activities were not altered by ethanol ingestion. The present study demonstrates that hepatic regucalcin concentration is decreased independent of mRNA expression in the STZ-diabetes and during ethanol ingestion in rats.
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  • 28
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    Molecular and cellular biochemistry 163-164 (1996), S. 231-237 
    ISSN: 1573-4919
    Keywords: extracellular matrix ; angiotensin II ; fibrillar collagen ; cardiac fibrosis ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Recent studies suggest that angiotensin II (angiotensin) may be involved in the regulation of metabolism of the cardiac extracellular matrix (ECM). Two major components of ECM are collagen types I and III which play an important role in maintaining the structure and function of the heart. Although the cellular metabolism of collagen is very complex (especially at the posttranslational level), we chose to address events that occur relatively early in the synthesis of cardiac collagen molecules. To gain an understanding of the role of angiotensin in the regulation of cardiac collagen gene expression, we studied the effect of three different doses of angiotensin (12, 24, and 48 μg/kg/h) on adult heart and cultured neonatal cardiac fibroblasts. The steady-state mRNA abundance of collagen types I and III was monitored using Northern blot analysis in both left and right ventricular samples at day 3 of angiotensin infusion and in cultured cardiac fibroblasts stimulated with angiotensin. In all mRNA abundance studies, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) signal was used to normalize the data for possible differences in loading and/or transfer of total RNA. Both collagen types I/GAPDH and III/GAPDH mRNA signal ratios were increased significantly in left ventricle in all dose regimens used for angiotensin infusion. Only the collagen type I/GAPDH mRNA signal ratio was increased in right ventricle with angiotensin infusion. Angiotensin (10−7-10−5 M) had no effect on the steady-state mRNA abundance of collagen genes in cultured neonatal cardiac fibroblasts after 24 h treatment in serum-free conditions. Our results confirm that infusion of angiotensin may upregulate steady-state collagen gene mRNA abundance in the heart. Angiotensin had no observable effect on collagen mRNA abundance in neonatal fibroblast culture. An explanation for the current results may be that angiotensin causes the release of undefined factors from cardiac myocytes, and that these secondary factors may be involved in either the activation of collagen gene transcription or in alteration of stability of collagen mRNA transcripts via a paracrine mechanism. Although our results indicate hemodynamic loading may potentiate the action of angiotensin, this scenario is unlikely as collagen type I gene expression was increased in the normotensive right ventricle.
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  • 29
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    Molecular and cellular biochemistry 167 (1997), S. 169-177 
    ISSN: 1573-4919
    Keywords: tamoxifen ; interferon ; gene expression ; breast cancer
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    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The molecular basis for the enhanced growth inhibition of MCF-7 human breast cancer xenografts by a combination of human interferon-β (IFN-β) and tamoxifen was investigated. Treatment of MCF-7, MDA-MB-231, and BT-20 cells with the combination of IFN-β and tamoxifen resulted in enhanced antiproliferative effects in vitro. Treatment with the combination of IFN-β and tamoxifen enhanced the expression of several IFN-β-inducible genes in human breast carcinoma cell lines relative to levels induced by IFN-β alone. Tamoxifen alone did not induce transcription of IFN-stimulated genes (ISGs). Augmentation of ISG expression by the combination of IFN-β and tamoxifen was noted in breast tumor cell lines irrespective of their functional estrogen receptor (ER) status or their dependence on estradiol for growth, suggesting that upregulation of ISGs was independent of ER status. Enhancement of IFN-stimulated gene expression by tamoxifen occurred at the transcripti onal level. Expression of transfected reporter genes under the control of IFN-α/β regulated promoters was also enhanced in IFN-β and tamoxifen-treated cells. Similarly, transcriptional induction of chimeric reporter plasmids driven by an IFN-γ inducible promoter (GAS; IFN-γ activated site) was also enhanced by the combination of IFN-γ and tamoxifen. In tamoxifen treated cells, IFN-β and IFN-γ readily activated transcription factors ISGF-3 and GAF, respectively. Therefore, augmentation of ISG expression by tamoxifen is an early event in the antitumoral activity of this drug combination. (Mol Cell Biochem 167: 169-177, 1997)
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    Molecular and cellular biochemistry 172 (1997), S. 47-57 
    ISSN: 1573-4919
    Keywords: smooth muscle ; gene transfer ; DNA ; RNA ; ribozyme ; liposome ; lipoxygenase ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Chemically synthesized hammerhead-type ribozymes targeted against the porcine leukocyte-type 12-lipoxygenase (LO) have been developed and studied. One chimeric ribozyme consists of DNA in the non-enzymatic portions, and RNA in the enzymatic core as well as two phosphorothioate internucleotide linkages at 3′ terminus. The second ribozyme consists of ribonucleotide sequences generated by in vitro transcription. In this chapter we describe methodologies to first analyze the ribozyme catalytic activity in vitro by studying cleavage of target RNA in vitro. The subsequent sections will describe how to target the catalytic ribozyme and deliver it to porcine vascular smooth muscle cells (PVSMC) by a liposome-mediated method. Finally ways to evaluate its activity to inhibit expression of the 12-LO mRNA will be presented. These results demonstrate the feasibility of using ribozymes as novel candidates for therapeutic agents to block specific gene expression in vascular cells.
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  • 31
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    Keywords: heart ; DNA ; library ; gene expression
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    Notes: Abstract The availability of high quality cDNA libraries is often crucial to the successful identification and characterization of genes. The concepts and potential pitfalls of constructing cDNA libraries are presented. Various applications requiring high quality cDNA libraries are outlined, including large-scale single pass sequencing of cDNA clones to generate expressed sequence tags (ESTs) and differential screening of cDNA libraries. The usefulness of combining such approaches for the discovery of novel disease-related and cardiovascular-based ESTs (CVBest) is discussed.
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  • 32
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    Molecular and cellular biochemistry 173 (1997), S. 59-69 
    ISSN: 1573-4919
    Keywords: hydrogen peroxide ; oxidative stress ; gene expression ; lens epithelial cells ; N-acetylcysteine ; pyrrolidine dithiocarbamate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The involvement of H2O2 in cataract development has been established inboth human patients and animal models. At the molecular level H2O2 has beenobserved to cause damage to DNA, protein and lipid. To explore the oxidativestress response of the lens system at the gene expression level, we haveexamined the effects of H2O2 on the mRNA change of the proto-oncogenes,c-jun, c-fos and c-myc in a rabbit lens cell line, N/N1003A. H2O2 treatmentof the rabbit lens epithelial cells for 60 min induces quick up-regulationof both c-jun and c-fos mRNAs. The maximal induction is 38 fold for c-jun at150 µM and 72 fold for c-fos at 250 µM H2O2. Treatment ofN/N1003A cells with 50-250 µM H2O2 for 60 min leads to a 2-5 foldincrease of the c-myc mRNA level. H2O2 also induces an up-regulation intransactivity of the activating protein-1 (AP-1) as shown with a reportergene driven by a prolactin gene promoter with 4 copies of AP-1 binding sitesinserted in the upstream of the promoter. Maximal induction occurs with 150µM H2O2. In the same system, the antioxidants, N-acetyl-cysteine (NAC)and pyrrolidine dithiocarbamate (PDTC) at concentrations shown toup-regulate the mRNAs of both c-jun and c-fos, also enhance thetransactivity of AP-1. NAC and PDTC have different effects in modulating theinduction of AP-1 activity by H2O2 and TPA. These results reveal thatoxidative stress regulates expression of various regulatory genes in lenssystems, which likely affects cell proliferation, differentiation andviability and thus affect normal lens functions.
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  • 33
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; cDNA cloning ; gene expression ; mouse liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The molecular cloning of the cDNA coding for a Ca2+-binding proteinregucalcin and its mRNA expression in mouse liver were investigated. ThecDNA clone encoding a regucalcin was isolated from a mouse liver cDNAlibrary and sequenced. Analysis of the sequence of the cloned cDNA showedthat the cDNA encoded the complete amino acid sequence of the mouseregucalcin molecule; the cDNA had an open reading frame of 897 bp. Mouseregucalcin was composed of 299 amino acid residues, and its molecular weightwas estimated to be 33,406 Da. The amino acid sequence of mouse regucalcinhad 94% homology, as compared with that of rat regucalcin. Northernblot analysis with the mouse liver cDNA probe revealed that mouse regucalcinmRNA was mainly present in the liver but only slightly in the kidney with asize of 1.8 kb. Hepatic regucalcin mRNA level of male mouse was higher thanthat of female mouse. A single intraperitoneal administration of calciumchloride (5, 15, and 30 mg Ca2+/100 g body weight) to mice induced aremarkable increase in regucalcin mRNA in the liver; the increase inregucalcin mRNA levels at 30 min after calcium administration wasdose-dependent. The present results demonstrate that regucalcin mRNA in miceis uniquely expressed in the liver, and that its expression is stimulated bycalcium administration.
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  • 34
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    Molecular and cellular biochemistry 176 (1997), S. 273-279 
    ISSN: 1573-4919
    Keywords: cardiac hypertrophy ; myosin heavy chain ; gene expression ; adrenergic system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Growth of the heart in hypertrophy is accompanied by changes in the phenotypic expression of cardiac genes. To explore the molecular basis of cardiac hypertrophy, we have analyzed the regulation of myosin heavy chain gene (MHC) expression. In one set of experiments, pressure overload on the rat heart was produced by constriction of the abdominal aorta. Changes in the α and β-MHC mRNA were then studied in overloaded hearts and following load removal. Pressure overload resulted in down-regulation of the α-MHC with corresponding up-regulation of the steady state level of β-MHC mRNA. Load removal (debanding) resulted in regression of cardiac hypertrophy and a rapid return of α-MHC mRNA to normal values. In contrast, the recovery in β-MHC mRNA was much slower to the extent that it remained substantially elevated compared to respective sham controls even after 7 weeks of post-debanding. These results suggest that putative load-related signals independently regulate two genes. Several lines of evidence indicate that adrenergic nervous system plays an important role in the induction and maintenance of cardiac hypertrophy and in the redistribution of myosin isoforms. We have analyzed the effect of cAMP inducing agents on the regulation of a-MHC gene in primary cultures of the fetal (18 day) rat cardiac myocyte. Inclusion of 8 Br-cAMP in the culture media increased the expression of α-MHC promoter/reporter construct comprising of 2.9 kb upstream sequence of the α-MHC gene. Several deletion mutations in the α- MHC gene promoter defined the cAMP responsive boundaries to be a 32 bp region comprising of -71 to -40 bp sequences. Deletion of this region resulted in loss of cAMP response as well as in basal expression of α-MHC promoter/reporter construct. These data suggest a role of β-adrenergic pathway in the modulation of α-MHC gene expression.
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  • 35
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    Keywords: regucalcin ; Ca2+-binding protein ; protein kinase C ; Ca2+signaling ; gene expression ; H4-II-E hepatoma cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The expression of hepatic Ca2+-binding protein regucalcin in the cloned rat hepatoma cells (H4-II-E) was investigated. The change in regucalcin mRNA levels was analyzed by Northern blotting using rat liver regucalcin complementary DNA (0.9 kb of open reading frame). Regucalcin mRNA was expressed in H4-II-E hepatoma cells. This expression was clearly stimulated in the presence of serum (10% fetal bovine serum). Bay K 8644 (2. 5 × 10-6 M), a Ca2+ channel agonist, significantly stimulated regucalcin mRNA expression in the absence or presence of 10% serum. Dibutyryl cyclic AMP (10-3 M) did not have a stimulatory effect on the regucalcin mRNA expression. The presence of phorbol 12-myristate 13-acetate (PMA; 10-6 M) or estrogen (10-8 M) caused a significant increase in regucalcin mRNA levels in the hepatoma cells cultured in serum-free medium, while insulin (5 × 10-9 M) or dexamethasone (10-6 M) had no effect. Bay K 8644-stimulated regucalcin mRNA expression in the hepatoma cells was completely blocked in the presence of trifluoperazine (10-5 M), an antagonist of calmodulin, or staurosporine (10-7 M), an inhibitor of protein kinase C. The stimulatory effect of PMA was clearly inhibited in the presence of stauroporine. The present study demonstrates that regucalcin mRNA is expressed in the transformed H4-II-E hepatoma cells, and that the expression is stimulated through Ca2+-dependent signaling factors.
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  • 36
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    Molecular and cellular biochemistry 199 (1999), S. 189-200 
    ISSN: 1573-4919
    Keywords: lung ; cancer ; urokinase ; receptor ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The urokinase-type plasminogen activator (uPA) interacts with its receptor (uPAR) to promote proteolysis as well as cell proliferation and migration. These functions contribute to the pathogenesis of neoplastic growth and invasiveness. Expression of uPAR in tumor extracts also inversely correlates with prognosis in many forms of cancer. In this study, we sought to determine if differences in uPAR expression were distinguishable between cultured human lung carcinoma and malignant mesothelioma subtypes. We also sought to determine if, as in malignant mesothelioma cells, uPAR expression is regulated at the posttranscriptional level in cultured malignant lung carcinoma cells. Using 125I-uPA binding and ligand blotting techniques, uPAR was expressed by phenotypically diverse lung carcinoma cell lines, including the H460, H157 and H1395 non-small cell lines and the H146 small cell lung carcinoma line. Increased uPAR expression was also detected in spindle-shaped (M33K) and epithelioid (M9K and MS-1) malignant mesothelioma cells. Selected mediators, including TGF-β, TNF-α, LPS and PMA, uniformly enhanced uPAR expression in each of the tumor cell lines. Steady state uPAR mRNA expression was determined by RNase protection assay and correlated directly with the changes in cell surface uPAR expression. By gel mobility shift and UV-cross linking assays, a uPAR mRNA binding protein (uPAR mRNABp) implicated in the posttranscriptional control of message stability, was identified in each of the cell lines. Expression of uPAR and its message in cultured lung carcinoma and malignant mesothelioma cells is similarly influenced by effectors present in the tumor microenvironment. Regulation of the uPAR message occurs at the posttranscriptional level in cultured small and non-small cell lung carcinoma cells as well as spindle-shaped and fibrous malignant mesothelioma cell lines. Posttranscriptional regulation of uPAR in all these cells involves the interaction of the uPAR mRNABp with uPAR mRNA, which promotes uPAR mRNA destabilization.
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  • 37
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    Biochemical genetics 18 (1980), S. 353-364 
    ISSN: 1573-4927
    Keywords: carboxylesterase ; electrophoretic variants ; fish development ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two esterases splitting α-naphthylacetate have been found in the tissues of adult loaches and in embryos. These were identified as arylesterase (E-1) (arylester hydrolase, E.C. 3.1.1.2) and carboxylesterase (E-2) (carboxylic ester hydrolase, E.C. 3.1.1.1.). In unfertilized loach eggs E-1 and E-2 synthesized during oogenesis were found. Active E-2 synthesized under the control of E-2 genes of the embryo appeared in embryos from the stage of 40–50 h of development. Maternal E-2 molecules synthesized in oogenesis or on the stored templates in embryogenesis persisted in larvae up to days 5–6 of development. Two genes controlling the synthesis of two forms of E-2 differing in electric mobility were found in the loach population from the delta of the Danube. The genes for fast and slow E-2 were shown to segregate in meiosis and to be allelic.
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  • 38
    ISSN: 1573-4927
    Keywords: glycophorins ; gorilla ; evolution ; gene family ; gene expression
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Homologues of MN blood group antigens, encoded by members of the glycophorin A (GPA) gene family, are expressed in man, anthropoid apes, and some species of Old World monkeys. Previous studies had shown that a three-gene framework, most closely related to that in man, is present in the chimpanzee. Here we report the genomic structure, transcript map, and protein expression of the GYPA locus in gorillas. Compared to the corresponding human and chimpanzee homologues, gorilla GPA, GPB, and GPB/E genes each showed a high degree of sequence identity, with the same exon-intron organization. However, the expression of exons III, IV, or V encoding the extracellular or membrane domains of homologous glycophorins varied among the three species. Gorilla GPA and GPB/E genes were unique in that the former occurred in two allelic forms with or without the expression of exon III, whereas the latter contained one (ψ exon III) instead of two silenced exons (ψ exons III and IV). Differences from human but not chimpanzee GPA also included the presence of a hybrid M/N epitope and the absence of the sequon for N-glycosylation. Owing to the retention of a functional exon III, gorilla GPB was more similar to chimpanzee GPB than human GPB. A transspecies allele was identified in the gorilla that gave rise to the Henshaw (He)-like antigen similar to that found in man. These results provide further insight into the model for evolution of the GPA gene family, indicating that the mechanisms underlying inter- and intraspecific polymorphism of glycophorins could predate the divergence of gorillas as the consequence of gene duplication and diversification.
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  • 39
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    Molecular and cellular biochemistry 172 (1997), S. 37-46 
    ISSN: 1573-4919
    Keywords: gene transfer ; gene expression ; adenovirus ; blood vessel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Adenovirus-mediated gene transfer is a promising method for studies of vascular biology and potentially for gene therapy. Intravascular approaches for gene transfer to blood vessels in vivo generally require interruption of blood flow and have several limitations. We have used two alternative approaches for gene transfer to blood vessels in vivo using perivascular application of vectors. First, replication-deficient adenovirus expressing nuclear-targeted bacterial b-galactosidase was injected into cerebrospinal fluid via the cisterna magna of rats. Leptomeningeal cells over the major arteries were efficiently transfected, and adventitial cells of large vessels and smooth muscle cells of small vessels were occasionally stained. When viral suspension was injected with the rat in a lateral position, the reporter gene was expressed extensively on the ipsilateral surface of the brain. Thus, adenovirus injected into cerebrospinal fluid provides gene transfer in vivo to cerebral blood vessels and, with greater efficiency, to perivascular tissue. Furthermore, positioning of the head may ‘target’ specific regions of the brain. Second, vascular gene delivery was accomplished by perivascular injection of virus in peripheral vessels. Injection of the adenoviral vector within the periarterial sheath of monkeys resulted in gene transfer to the vessel wall that was substantial in magnitude although limited to cells in the adventitia. Approximately20% of adventitial cells expressed the transgene, with no gene transfer to cells in the intima or media. These approaches may provide alternative approaches for gene transfer to blood vessels, and may be useful for studies of vascular biology and perhaps vascular gene therapy.
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  • 40
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    Molecular and cellular biochemistry 172 (1997), S. 111-120 
    ISSN: 1573-4919
    Keywords: differential display ; cardiac development ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract An estimated 15,000 different mRNA species are expressed in a typical mammalian cell. The differential expression of mRNAs in both a temporal and cell-specific manner determines the fate of the cell and creates the organism. Analysis of this differential gene expression has become a central aim of many laboratories attempting to understand the mechanisms underlying various biological processes. Currently, we are using a technique called differential display to analyze the differential expression of genes in cardiomyocytes. Differential display is a rapid and powerful technique that was introduced by Liang and Pardee in 1992. Since that time, it has been successfully applied by several groups, and it is quickly becoming a standard method for studying differential gene expression. Here, we present a detailed article discussing the differential display methodology and how we have utilized it to identify potential genes involved in cardiomyocyte proliferation. Furthermore, we have provided a list of materials and supplied examples of data obtained, in an effort to allow the reader to perform the technique with success in their own laboratory.
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  • 41
    ISSN: 1573-4919
    Keywords: plasminogen activators ; plasminogen activator inhibitors ; gene expression ; left ventricular hypertrophy ; pressure overload
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract In the early stages of left ventricular hypertrophy (LVH) acute adaptive changes occur in the coronary vasculature as it remodels. Plasminogen activators (PAs) and inhibitors (PAIs) have the potential effects of proteolytic degradation that is relevant to tissue remodeling and angiogenesis. Our study focused on the possible roles of PAI-1, PAI-2, uPA and tPA in myocyte hypertrophy and angiogenesis in the early and late stages of pressure overload induced left ventricular hypertrophy (LVH). We divided seventeen adult swine, weighing 24.2 ± 6.5 kg, into four groups: control, sham-operated, early LVH and late heart failure LVH group. At surgery we placed a fixed constrictor on the ascending aorta immediately above the aortic valve. This increased LV systolic pressure from 133 ± 15 to 193 ± 24 mm Hg after the surgery. We subdivided the early group into groups of 3 animals each that we euthanized at 8, 24 and 72 h after operation and obtained heart samples for analysis. In the late heart failure group individual animals were euthanized at 55, 59, 62 and 72 days after the detection of congestive heart failure. We also obtained tissue samples from the control and sham-operated swine. Sections for histologic analysis were fixed in 10% buffered formalin. We isolated RNA, size fractionated it using 1% formaldehyde-agarose gel electrophoresis and then did Northern blots. The mRNAs from both PAI-1 and PAI-2 showed a remarkable increase at 8 and 24 h after acute aortic constriction and returned to control by 72 h. Regional differences showed that most of the increases were in the endocardium. Three animals in the late heart failure LVH group were determined to be in congestive heart failure at about 2 months after the onset of aortic constriction. In these animals PAI-1 and PAI-2 were increased in both the left and right ventricles but remained low in an animal of the same elevation in aortic pressure seen by the LV who did not have congestive failure. These data suggest that PA and PAI gene expressions change before morphologic changes occur in the early stages of developing LVH. Also at the time of onset of congestive heart failure this increased expression reappears. PAs and PA inhibitors mRNA levels vary in the different regions of the heart reflecting changing wall stresses. Thus, the PAs and PA inhibitors may play an important role in angiogenesis that occurs during the early stages of LVH. The increased expression in the late stage of LVH may reflect further changes in wall stresses since these animals also showed overt clinical signs of heart failure.
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  • 42
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    Molecular and cellular biochemistry 178 (1998), S. 157-162 
    ISSN: 1573-4919
    Keywords: protein tyrosine phosphatases ; gene expression ; degenerate deoxyoligonucleotides ; RT-PCR ; Swiss 3T3 fibroblasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The aim of this study was to identify protein tyrosine phosphatases (PTPs) expressed in Swiss 3T3 fibroblasts and to examine their expression levels as well as to characterize quantitative aspects of RT-PCR based on degenerate deoxyoligonucleotides. By using an RT-PCR assay based on degenerate deoxyoligonucleotide primers, expression of mRNAs for two cytoplasmic- and six transmembrane-type PTPs in Swiss 3T3 cells was detected. The sequences of two of them are new. Among nine analyzed PTPs expressed to widely varied extends, only three have mRNA levels high enough to be seen on Northern blots with 10 µg of total RNA per lane. The frequencies with which the examined PTPs are represented among the PCR amplification products, correlate stronger with the primer fidelity, defined as the number of mismatches between the primer- and the cDNA target-sequences, rather than with the PTP expression levels. In conclusion, an RT-PCR assay based on degenerate primers can be successfully used to sample the expressed PTPs and to identify new members of this gene family. However, reliable quantification of their mRNA levels can only be achieved using the classical approaches, like Northern, RNase protection assay or non-degenerate quantitative RT-PCR.
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  • 43
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    Molecular and cellular biochemistry 162 (1996), S. 51-58 
    ISSN: 1573-4919
    Keywords: metabolism ; glucose transporter ; adipocytes ; gene expression
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    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We tested the hypothesis that the constitutive glucose transporter (GLUT 1) in 3T3-L 1 adipocytes belongs to the family of glucose-regulated proteins which are transcriptionally regulated by glucose deprivation. Using cDNA probes for both GRP78 (BiP) and GLUT1, we show that the level of GRP78 mRNA increased by 15-fold within 24 h of glucose deprivation with little change in GLUT1 mRNA. The elevated GRP78 mRNA in turn led to a time-dependent increase in GRP78 protein. While glucose deprivation did not alter the expression of the normal glycoform of GLUT 1, a lower molecular weight glycoform accumulated with extended deprivation. Mannose and fructose, but not galactose, prevented the induction of GRP78 and accumulation of the abnormal GLUT1. Because GRP78 acts as a chaperone in other cell systems, we also sought evidence to support this activity in 3T3-L1 adipocytes. Using the technique of co-immunoprecipitation, we demonstrate that GRP78 bound several proteins unique to the glucose-deprived state. No deprivation-specific proteins could be detected in association with GLUT 1. These data lead us to conclude that GLUTl does not display characteristics of the glucose-regulated proteins, at least in 3T3-L1 adipocytes, a widely used model for differentiation, hormone action, and nutrient control. However, the mechanisms for activating traditional members of this family appear intact.
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  • 44
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    Molecular and cellular biochemistry 186 (1998), S. 43-51 
    ISSN: 1573-4919
    Keywords: myocardial ischemia ; gene expression ; growth factors ; phospholamban ; calsequestrin heat shock proteins ; preconditioning ; stunning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Brief periods of coronary occlusion render the affected myocardium more tolarant to the otherwise devastating effects of long coronary occlusion. Besides this phenomena, called ischemic preconditioning, short periods of ischemia cause a regional dysfunction, namely myocardial stunning. The molecular mechanisms of both syndromes are not very well understood. We therefore investigated the expression of genes which may be involved in cardioprotection or repair processes.Using our porcine model of ischemia and reperfusion we were able to show an induction of genes coding for transcription factors (proto-oncogenes), for proteins involved in repair processes (heat shock genes), for proteins implicated in the calcium homeostasis (calcium-handling genes) and for growth factors. We could show that the increased mRNA levels are due to an enhanced transcriptional activity and not to a prolonged half-life of the transcripts. The angiogenic growth factor vascular endothelial growth factor (VEGF) represents an exception. It exhibits - in addition to a HIF-motif (Hypoxia Inducible Factor) in its promoter/enhancer - a protein binding region in its 3′ UTR which when occupied renders the mRNA more stable. However to what extent the expression of the distinct genes contributes to the cardioprotective effect of ischemic preconditioning or myocardial stunning can only be presumed. Increased mRNA stability can be confered via adenosine which is produced during ischemia by ATP-breakdown. The demasking of unknown genes - via differential display reverse transcription polymerase chain reaction (DDRT-PCR) - should provide a more comprehensive view of the mechanisms underlying both processes.
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  • 45
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    Molecular and cellular biochemistry 201 (1999), S. 111-123 
    ISSN: 1573-4919
    Keywords: complement factor I ; TPA ; protein kinase C ; gene expression ; Hep G2 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract This study examined the role of the protein kinase C (PKC) signalling pathway in the regulation of expression of human complement factor I (CFI) gene. The production of CFI by Hep G2 cells was enhanced in a dose- and time-dependent fashion by 12-O-tetradecanoyl-1,2-phorbol 13-acetate (TPA), a potent PKC activator. 4α-phorbol didecanoate, an inactive phorbol ester, had no effect on CFI synthesis. The TPA-dependent increase in CFI secretion was correlated with an increase in CFI mRNA levels. Forskolin, a cAMP-inducing agent, augmented the TPA response. W7, an inhibitor of protein kinase A and genistein, an inhibitor of protein tyrosine kinase(s) both did not prevent the increase in CFI expression mediated by TPA. However, calphostin C, a specific inhibitor of PKC, abolished the TPA-induced increase in CFI mRNA levels. Down regulation of intracellular PKC levels by prior exposure of Hep G2 cells to a high concentration of TPA also blocked the increase in CFI mRNA levels induced by TPA suggesting that the TPA effects were mediated via activation of PKC. mRNA decay studies indicated that the half-life of CFI mRNA in TPA-induced cells was not significantly different from control. Nuclear run-on transcriptional assays on the other hand demonstrated that whereas the CFI gene is transcribed under basal conditions in Hep G2 cells, TPA induced a 3-4 fold increase in the transcription rate of CFI gene in 24 h. The transcription rate of GAPDH gene did not change, indicating that the effects were not general on gene transcription. Transient transfections of Hep G2 cells with chloramphenicol acetyltransferase reporter gene (CAT) constructs containing a series of sequential 5′ deletions of the CFI promoter and CAT assays showed that the sequence between -136 and -130, containing an AP-1 consensus sequence (TGAGTCA) was required for the TPA response. This observation was substantiated by the finding that mutation of this AP-1 site to TttaTCA or TtAtcCA abolished the TPA responsiveness. The enhancement of the activity of transfected chimeric CAT constructs by TPA was abrogated by calphostin C and by pyrrolidine dithiocarbamate (an inhibitor of NF-κB and AP-1 transactivation). These results indicate that TPA regulation of CFI gene requires PKC signalling and is mediated by via a TPA response element (TRE) in the CFI promoter region located at -136/-130 and involves the transactivation of AP-1 and NF-κB transcription factors. We suggest that PKC may be one of the intracellular pathways that control CFI gene expression and that cellular processes (involving growth factors, hormones, cytokines etc.) that activate PKC may upregulate the expression of the CFI gene.
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  • 46
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    Keywords: regucalcin ; calcium-binding protein ; gene expression ; Ca2+-ATPase ; brain microsomes ; aging
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    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The expression of calcium-binding protein regucalcin and its effect on the microsomal Ca2+-ATPase activity in rat brain tissues was investigated. The expression of regucalcin mRNA was demonstrated by reverse transcription-polymerase chain reaction (RT-PCR) analysis in brain tissues using rat regucalcin-specific primers. Regucalcin concentration in the brain tissues was about 5 × 10-9 M as measured using enzyme-linked immunoadsorbent assay (ELISA), and this level was lowered with increasing age (50 weeks old). The presence of regucalcin (10-9 to 10-7 M) in the enzyme reaction mixture caused a significant decrease in Ca2+-ATPase activity in the brain microsomes of young rats (5 weeks old). Meanwhile, the enzyme activity was not significantly altered by the addition of calmodulin (1 or 50 μg/ml), calbindin (1 or 10 μg/ml), and S-100 A protein (5 or 25 μg/ml), which are other Ca2+-binding proteins in rat brain. The effect of regucalcin to inhibit microsomal Ca2+-ATPase activity was weakened in the brain of rats with increasing age (50 weeks old). The present study demonstrates that regucalcin is expressed in the brain, and that it can uniquely inhibit Ca2+-ATPase activity in the brain microsomes of rats. The findings suggest that regucalcin plays a role in the regulation of microsomal Ca2+-ATPase activity in rat brain tissues.
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  • 47
    ISSN: 1573-4927
    Keywords: amphibian development ; allelic isozyme variants ; gene expression ; maternal effects
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The polymorphism of three enzymes [lactate dehydrogenase B (LDH-B), glucose-6-phosphate dehydrogenase, (G6PDH), and peptidase-1 (PEP-1)] in Pleurodeles waltl has allowed the expression of the corresponding loci to be followed during the development of spawnings arising from various crosses. A maternal effect lasting up to the late tail-bud stage (approx. stage 28) was shown for PEP-1. A similar situation was observed for LDH-B and G6PDH. The embryonic alleles present retarded expression: from about stage 28 for PEP-1 and G6PDH and from about stages 22 to 24 (the young tail-bud stage) for LDH-B.
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  • 48
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    Biochemical genetics 22 (1984), S. 901-911 
    ISSN: 1573-4927
    Keywords: cat hemoglobins ; cell-free translation ; polymorphism ; gene expression
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The molecular basis for the genetic control of variable proportions of the two hemoglobins in domestic cat blood was investigated. Both major hemoglobins of cat blood, HbA (α2β 2 A ) and HbB (α2β 2 B ), were synthesized in an mRNA-dependent rabbit reticulocyte system using poly(A)-RNA from cat reticulocyte polysomes as the source of the message. The relative amounts of HbA and HbB synthesized in the system were a function of the HbA/HbB phenotype of the cat from which the reticulocytes and poly(A)-RNA were obtained. Higher ratios of HbA/HbB synthesis were found when the source of poly(A)-RNA was the polysomes from a 90/10 (HbA/HbB) phenotype than when it was from a 50/50 (HbA/HbB) phenotype. These results indicate that the variable proportions of HbA and HbB found in the blood of different members of the cat population result from the genetic control of the relative amounts of functional βA and βB mRNA.
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  • 49
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    Molecular and cellular biochemistry 151 (1995), S. 55-60 
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium ; gene expression ; kidney damage ; rat kidney cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The alteration of Ca2+-binding protein regucalcin mRNA expression in the kidney cortex of rats administered cisplatin and cephaloridine, which can induce kidney damage, was investigated. Cisplatin (0.25, 0.5 and 1.0 mg/100 g body weight) or cephaloridine (25, 50 and 100 mg/100 g) was intraperitoneally administered in rats, and 1, 2 and 3 days later they were sacrificed. The alteration in serum findings after the administration of cisplatin (1.0 mg/100 g) or cephaloridine (50 and 100 mg/100 g) demonstrated chemically induced kidney damage; blood urea nitrogen (BUN) concentration increased markedly and serum inorganic phosphorus or calcium concentration decreased significantly. Moreover, the administration of cisplatin (1.0 mg/100 g) or cephaloridine (100 mg/100 g) caused a remarkable increase of calcium content in the kidney cortex of rats, indicating kidney damage. The expression of regucalcin mRNA in the kidney cortex was markedly reduced by the administration of cisplatin or cephaloridine in rats, when the mRNA levels were analyzed by Northern blotting using rat liver regucalcin cDNA (0.9 kb). The mRNA decreases were seen with the used lowest dose of cisplatin or cephaloridine. The present study clearly demonstrates that the mRNA expression of Ca2+-binding protein regucalcin in the kidney cortex of rats is decreased by chemically induced kidney damage.
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  • 50
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    Molecular and cellular biochemistry 152 (1995), S. 131-141 
    ISSN: 1573-4919
    Keywords: gene expression ; mRNA ; proto-oncogenes
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    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Polyomavirus large T-antigen transgenic mice develop cardiac hypertrophy characterized by an increase in atrial natriuretic factor and β-myosin heavy chain isoform expression. The aim of this study was to examine changes in proto-oncogene expression in hypertrophied hearts from the transgenic mice. Expression of early growth response-1 (Egr-1) mRNA was detected in hearts from all 15 transgenic mice, but was not detectable in 13 control mice. Reverse transcriptase-polymerase chain reaction experiments usingEgr-1-specific primers confirmed the increase inEgr-1 mRNA in enlarged hearts from the transgenic mice. Expression of c-jun,junD and Ha-ras mRNAs was increased in the transgenic hearts 3, 17 and 2.8-fold, respectively. Western blots showed an increase in c-myc, c-jun and ras protein in hypertrophied transgenic hearts. Immunofluorescence analyses confirmed an increase in Egr-1 and c-jun protein in transgenic cardiomyocytes. Proliferating cell nuclear antigen, Ki-ras and HSP 90 mRNAs were decreased 22, 2.7 and 3-fold, respectively in the transgenic hearts. Not altered in most hypertrophied hearts was expression of c-fos, junB, p53, c-neu, c-myc, HSP70, HSP27, TGF-β or IGF-1 mRNAs. Proto-oncogene and growth factor gene expression in hypertrophy induced by PVLT expression is modulated, with some proto-oncogenes increased and others decreased in expression.
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  • 51
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    Molecular and cellular biochemistry 154 (1996), S. 65-70 
    ISSN: 1573-4919
    Keywords: gene expression ; regulatory elements ; plasmid ; oligonucleotides
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    Notes: Abstract A potentially powerful pharmacological approach to modulating the expression of specific, disease-related genes involves the inhibition of transcription factor binding to promoter or enhancer elements through oligonucleotide-mediated triple-helix formation. In vivo, the typical target for intermolecular triplex formation would most likely be torsionally-strained rather than relaxed duplex DNA. To determine the effects of strained DNA on triplex formation, we investigated the interactions between a G/T rich oligonucleotide and both supercoiled and relaxed plasmid DNA using a restriction endonuclease protection assay. Both the kinetics of formation and dissociation of purine-motif triplexes were unaffected by the conformational state of the duplex DNA. Similarly, the topological state of the plasmid targets was not affected by triplex formation. Taken together, these observations suggest that stable intermolecular triplexes can form in vivo under conditions of moderate torsional strain.
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  • 52
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    Keywords: estrogen ; apolipoprotein ; gene expression ; mice ; atherosclerosis
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    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Estrogen protects against developing premature coronary artery disease.However, the mechanism of protective effects of estrogen still remainspoorly understood. One mechanism by which estrogen can have protectiveeffects apppears to be through modulation of plasma lipoproteins. We showedthat the mouse can be used as animal model to study estrogen-mediatedsynthesis and secretion of lipoproteins since, unlike the rat, the mousedoes not up-regulate LDL receptors (Srivastava et al. [4]). Since inbredstrains of mice differ in their genetic background and show differingresponsiveness to dietary lipids, we examined how various inbred strains ofmice respond to estradiol administration, and whether some mouse strainsshow responses similar to rats. 17b-estradiol was administered to male micefrom 15 different inbred strains, and the changes in plasma levels oflipids, apoB, apoAI, and apoE were examined. Total cholesterol decreased inall but one strain, apoAI levels decreased in all but 3 strains while apoBlevels and apoB/apoAI ratios increased in all but 2 strains, suggesting thatin contrast to rats, the apoB-containing lipoproteins increased relative toHDL in all strains of mice examined. Basal and estradiol-induced changes intotal cholesterol were significantly correlated with changes in apoAI, butnot apoB, reflecting the predominance of HDL over other lipoproteins inmouse plasma. The effects of estrogen on plasma apoE levels varied amongvarious inbred strains of mice tested. Plasma apoE levels increased in sevenstrains treated with estrogen, and remained unchanged in the rest. Toexamine whether changes of plasma apoproteins are associated with thechanges in the respective hepatic mRNA levels, apoAI, B and E mRNA werequantified by RNase protection assay. Hepatic apoE mRNA did not showcorrelation with either basal or post treatment plasma apoE levels in any ofthe strains. Similarly, most of the mouse strains did not show correlationof plasma apoAI and apoB levels with the corresponding hepatic mRNA levels.These results suggest that estrogen regulates plasma lipoproteinconcentrations primarily by posttranscriptional mechansims, and there werestrain-related differences in the estrogen-mediated regulation oflipoprotein metabolism.
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  • 53
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    Keywords: regucalcin ; Ca2+-binding protein ; insulin ; gene expression ; HepG2 cells ; transformed cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The expression of hepatic Ca2+-binding protein regucalcin in the cloned human hepatoma cells (HepG2) was investigated. The change in regucalcin mRNA levels was analyzed by Northern blotting using rat liver regucalcin complementary DNA (0.9 kb of open reading frame). Regucalcin mRNA was expressed in HepG2 cells, although the mRNA was markedly expressed in normal rat liver. Moreover, regucalcin protein in HepG2 cells was detected by Western blot analysis using a polyclonal rabbit anti-regucalcin antibody. Regucalcin mRNA expression in HepG2 cells was clearly stimulated by the culture with insulin (10-8 M) of the effective concentration. Regucalcin protein in HepG2 cells was also increased by the treatment of insulin (10-8 M). The present results demonstrate that regucalcin is expressed in the transformed HepG2 cells, and that the expression is stimulated by insulin.
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  • 54
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    Molecular and cellular biochemistry 177 (1997), S. 1-6 
    ISSN: 1573-4919
    Keywords: gene expression ; mRNA secondary structure ; single tube RT-PCR ; TNF receptor I
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The secondary structure of human tumor necrosis factor receptor I (TNFR-I) mRNA based on its lowest folding energy was predicted. Three combinations of primers selected from open-regions and four combinations of primers from closed-regions of TNFR-I mRNA structure were employed for single-tube reverse transcription-polymerase chain reaction (RT-PCR) for the determination of TNFR-I gene expression in U937 cell. All the primers were designed with the same criteria. However, the different primers generated distinct quantities of RT-PCR products from the same concentration of TNFR-I mRNA, implying that the determination of gene expression by RT-PCR was affected by the mRNA secondary structure. In addition, the sensitivity of the open-region RT-PCR was approximately one hundred-fold higher than that in the closed-regions of TNFR-I mRNA. The low efficiency of the closed-region RT-PCR was not correlated with the G/C content of the TNFR-I mRNA structure. These results suggest that consideration of the influence of intrinsic mRNA structure of a gene is essential prior to the determination of gene expression by quantitative RT-PCR, and this open-region strategy of primer design may yield an efficient primer for in vitro amplification of cDNA by RT-PCR.
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  • 55
    ISSN: 1573-4919
    Keywords: cholesteryl ester ; CETP ; Caco-2 ; polymerase chain reaction ; gene expression ; mRNA ; alternative splicing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Cholesteryl ester transfer protein (CETP) is a plasma protein involved in the reverse cholesterol transport and expressed in several human tissues and cell lines. We studied CETP expression in Caco-2 cell line, a model of the human enterocyte epithelium. By reverse-transcriptase polymerase chain reaction, we could demonstrate that in basal condition Caco-2 cells have a low rate of expression of active CETP mRNA. Furthermore, we found that even in this cell line CETP mRNA alternative splicing occurs with deletion of exon 9 sequence. Densitometric analysis of the in vitro amplified fragments showed that under basal conditions about 60% of reverse transcribed CETP cDNA corresponds to exon 9-deleted transcripts. After challenge with 50 µM sodium oleate, there is a ∼2 fold increase in the transcription rate of the full-length CETP cDNA, as measured by competitive PCR, which is accompanied to an increased activity measured in the cell-conditioned medium. On the contrary, no significant change is seen in the amount of exon 9-deleted cDNA. Consequently, an inversion in the ratio of full-length and exon 9-deleted CETP cDNA is evident, suggesting that sodium oleate selectively enhances the expression of full-length CETP mRNA.
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  • 56
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    Molecular and cellular biochemistry 178 (1998), S. 283-287 
    ISSN: 1573-4919
    Keywords: regucalcin ; calcium-binding protein ; gene expression ; fetal development ; rat liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The expression of hepatic calcium-binding protein regucalcin mRNA in fetal rats was investigated. The alteration in regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin cDNA (0.9 kb with complete open reading frame). Hepatic regucalcin mRNA levels were progressively increased with fetal development; the mRNA was clearly expressed at 15 and 21 days of pregnancy but only slightly at the 8 days. Meanwhile, β-actin mRNA levels in the fetal liver were remarkable at 8 and 15 days of pregnancy. The fetal liver regucalcin mRNA levels at 15 days of pregnancy were significantly decreased by overnight-fasting of maternal rats. The oral administration of calcium chloride (50 mg Ca/100 g body weight) to maternal rats at 15 days of pregnancy caused a remarkable elevation (about 2 fold) of regucalcin mRNA levels in the fetal liver; this increase was seen 60 and 180 min after the calcium administration. After birth, regucalcin mRNA was increasingly expressed in the livers of newborn and weanling rats, while hepatic β-actin mRNA expression was not appreciably altered with increasing ages. These findings demonstrate that the expression of hepatic regucalcin mRNA is increased with fetal development, and that the gene expression may be stimulated by the ingestion of dietary calcium.
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  • 57
    ISSN: 1573-4919
    Keywords: extremely low frequency magnetic fields ; gene expression ; neuron derived orphan receptor-1 ; signal transduction ; Chinese hamster ovary K1 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Enhanced expression of neuron derived orphan receptor (NOR-1) gene was observed by exposure of Chinese hamster ovary K1 (CHO-K1) cells to an extremely low frequency magnetic field (ELFMF) of 50 Hz at 400 mT, but not at 5 mT. The enhanced expression, reaching the maximum at 6 h, was transient and reduced to the control level after exposure to 400 mT ELFMF for 24 h. The NOR-1 expression induced by treatment with forskolin and TPA was further enhanced by the simultaneous treatment with 400 mT ELFMF, in which the maximum response was at 3 h. The NOR-1 expression by these treatments was induced more earlier than that by 400 mT ELFMF alone. When cells were treated with an inhibitor of the protein kinase C (calphostin C or crocetin) and Ca2+ entry blockers (nifedipin and dantrolen) during the 400 mT ELFMF exposure, the enhanced NOR-1 expression was not observed. Exposure of CHO-K1 cells to the high-density 400 mT ELFMF may affect the signal transduction in the cells, resulting in the enhanced NOR-1 gene expression.
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  • 58
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    Molecular and cellular biochemistry 188 (1998), S. 41-48 
    ISSN: 1573-4919
    Keywords: zinc ; transcription factors ; gene expression ; organogenesis ; Xenopus laevis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Zinc regulates the gene expression machinery. It affects the structure of chromatin, the template function of its DNA, the activity of numerous transcription factors and of RNA polymerases. Hence, it determines both the types of mRNA transcripts synthesized and the rate of transcription itself. Alterations in one or more of these zinc dependent processes have been proposed to account for the proliferative arrest and teratology induced by zinc deficiency. To examine this proposal, studies of zinc during X. laevis development have been initiated. The kinetics of X. laevis oocyte zinc uptake and storage and of zinc utilization during embryogenesis have been examined first. Vitellogenin carries zinc into the oocyte. Ten % of the total zinc (10 ng/egg) remains within the cytosol while 90% (90 ng/egg) is stored in the yolk platelets associated with lipovitellin. The cytosolic pool is the source of the zinc for all newly formed metalloproteins involved in embryo development. The yolk platelet zinc pool is stored for later use during early metamorphosis. It is now possible to examine zinc transfer to molecules, such as e.g. transcription factors, and the role of the metal in their function in development and organogenesis.
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    Molecular and cellular biochemistry 189 (1998), S. 107-111 
    ISSN: 1573-4919
    Keywords: gene expression ; electromagnetic fields ; superinduction ; anisomycin ; immediate early gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Rat pheochromocytoma PC12 cells have been treated with nerve growth factor (NGF) at final concentrations of 2, 4, 8, and 16 ng/ml, and then were exposed to 60-Hz, sinusoidal magnetic fields (MF) of 12.5, 25, 50, and 100 μT (rms) for 30 min. Transcript levels for both c-fos and glyceraldehyde-3 -phosphate dehydrogenase were determined by Northern blot analysis using 32P-labeled cDNA probes. No change in c-fos expression was measured at any condition employed. Treatment of PC12 cells with a combination of agents (NGF, forskolin, and tetradecanoylphorbol acetate [TPA]) increased c-fos expression over that detected with NGF alone. MF exposure of cells treated with the three-agent regimen produced two outcomes, either no change or a doubling of c-fos expression. In subsequent experiments, cells were treated with NGF, NGF + forskolin + TPA, or pre-treated with anisomycin and then treated with NGF + forskolin + TPA. It was determined that MF exposure, like superinduction with anisomycin, increased c-fos expression only in cultures which were not yet exhibiting maximal c-fos expression. It is hypothesized that MF exposure, like anisomycin, may alter the activity of key intracellular protein kinases.
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  • 60
    ISSN: 1573-4919
    Keywords: mechanical stretch ; smooth muscle cells ; differential display ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Physical forces induce profound changes in cell phenotype, shape and behavior. These changes can occur in vascular structures as a result of pressure overload and their effects can be seen in atherosclerotic vessels in which smooth muscle cells have undergone hyperplastic and hypertrophic changes. At the molecular level, mechanical stimuli are converted into chemical ones and lead to modulation of gene expression and/or the activation of a new repertoire of genes whose encoded proteins help the cells to adapt to their microenvironment. In this study, we have used a two primer-based mRNA differential display technique to identify candidate mechano-responsive genes in pulmonary artery smooth muscle cells. As compared to the original method described by Liang and Pardee, this technique uses two arbitrary primers instead of an anchored oligo(dt) plus an arbitrary primer in the polymerase chain reaction. The chief advantages of these modifications are an increase in the efficiency of the amplification and in the identification of differentially expressed clones. Using this approach, we compared the pattern of expressed genes in cells cultured under static conditions with those in cells that were mechanically stretched (1 Hz) for 24 h in a well-defined in vitro mechanical system. Three candidate genes that showed reproducible differences were chosen for further characterization and cloning. One clone was under expressed in stretched cells and had a DNA sequence with 90% homology to the human fibronectin gene. Two other clones were highly expressed in stretched cells and had a 92% and a 83% sequence homology with human platelet-activating factor (PAF) receptor and rat insulin-like growth factor-I (IGF-I) genes respectively. Northern blot analysis confirmed low levels of fibronectin mRNA transcripts in stretched cells. In contrast, accumulation of PAF receptor mRNA occurred 30 min after mechanical stretch was initiated whereas IGF-I mRNA levels peaked at 8 h. Both mRNA levels were sustained for up to 24 h of mechanical stretching. These results demonstrate the usefulness of the two primer-based mRNA differential display that enabled us to identify and characterize alterations at the level of gene expression among matrix proteins, G-protein coupled receptors and growth factors, each of whose response to mechanical strain is different. A more complete understanding of these responses will provide further insight into the pathologic processes associated with hypertension and atherosclerosis.
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  • 61
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    Molecular biology reports 24 (1997), S. 221-230 
    ISSN: 1573-4978
    Keywords: gene expression ; ribonucleoprotein ; RNase MRP ; RNase P ; transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We report on the expression of mouse RNase MRP RNA in human embryonic kidney 293 cells upon DNA transfection. Stable cell lines were selected by cotransfection with a neo r gene. Transcription of wild-type and deletion mutants of MRP RNA and ribonucleoprotein formation were assessed by RNase protection and immunoprecipitation experiments. Mouse MRP RNA as expressed in 293 cells readily associates with human proteins to form a chimeric Th ribonucleoprotein. 5' truncated MRP RNAs, however, failed to associate with Th antigen(s) and deletion of the 3' sequences of MRP RNA greatly reduced the expression in stable as well as in transient transfectants. Abbreviations: nt(s) – nucleotide(s); RNP – ribonucleoprotein.
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  • 62
    ISSN: 1573-4978
    Keywords: gene expression ; nuclear matrix proteins ; ocular lens epithelial cells ; transcription factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Association of transcription factors with the nuclear matrix represents a mechanism by which nuclear architecture may influence transcriptional control of gene expression. This investigation examines nuclear matrix associated proteins (NMP's) isolated from ocular lens epithelial cells by monitoring DNA binding activities using consensus oligonucleotides recognized by the transcription factors YY1, AML-1, AP-1, SP-1 and ATF. The nuclear matrix fractions tested included an immortilized human lens epithelial cell line containing the SV40 large T-antigen, and two mouse lens epithelial cell lines derived from either a normal mouse or a cataract mouse. A rabbit epidermal epithelial cell line and HeLa cells were also included in this study for comparison. The data from these experiments reveal that ubiquitously represented and tissue restricted regulatory proteins are associated with nuclear matrix of lens epithelial cells. The functional significance of the nuclear matrix association of these transcription factors remains to be determined. However, our findings raise the possibility that the transcription factors associated with the nuclear matrix could have specific roles in gene regulation and eye tissue development.
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  • 63
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    Molecular biology reports 23 (1996), S. 205-210 
    ISSN: 1573-4978
    Keywords: autoantigen ; cDNA cloning ; gene expression ; ribonucleoprotein Ro ; 5′RACE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Autoantibodies to SS-A/Ro are among the most common found in sera of patients with systemic rheumatic diseases. These autoimmune diseases can affect various organ systems of the body and are variable in their manifestations and presentation. One of the autoimmune targets is the 60 kDa SS-A/Ro protein known to be associated with small cytoplasmic Y RNAs. To study systematically the expression of the protein, we have cloned the mouse full length 60 kDa SS-A/Ro cDNA using 5′ RACE based on a cDNA sequence reported in the mouse genome project. The recombinant protein derived from the putative full-length construct was shown to react with human prototype anti-SS-A/Ro serum Ge in western blot and immunoprecipitation and comigrated with cellular 60 kDa SS-A/Ro protein in 3T3 cells. Cellular expression, measured by RT-PCR, was highest in mouse brain, followed by lung, muscle, kindney and heart. Lower levels were found in testis, liver and spleen. Like the human 60 kDa SS-A/Ro protein, the deduced mouse homolog has 538 amino acids. Sequence analysis showed 89.9% identity and 95.0% similarity between the mouse and human proteins.
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  • 64
    ISSN: 1573-5028
    Keywords: β-fructofuranosidase ; invertase ; gene expression ; gene structure ; flower buds ; Daucus carota
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three genomic clones (Inv *Dc1, Inv *Dc2 and Inv *Dc3) were isolated by using the cDNA for carrot cell wall β-fructofuranosidase as a probe. The expression patterns of the three genes differed markedly. High levels of Inv *Dc1 transcripts were found in leaves and roots of young carrot, whereas in plants with developing tap roots no transcripts were detected. A high level of mRNA of Inv *Dc1 was also present in suspension-cultured cells. In developing reproductive organs, only low levels of transcripts of Inv *Dc1 were found in flower buds and flowers and none at later stages of development. In contrast, Inv *Dc2 and Inv *Dc3 were not expressed in vegetative plant organs. Invb1 *Dc1 was exclusively and strongly expressed in flower buds, and Inv *Dc3 at a very low level in suspension-cultured cells.
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  • 65
    ISSN: 1573-5028
    Keywords: fruit ; gene expression ; promoter ; ripening ; tomato ; transgenic plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 1.4 kb 5′ polygalacturonase (PG) gene-flanking region has previously been demonstrated to direct ripening-specific chloramphenicol acetyl transferase (CAT) expression in transgenic tomato plants. The steady state level of CAT mRNA in these plants was estimated to be less than 1% of the endogenous PG mRNA. Further constructs containing larger PG gene-flanking regions were generated and tested for their ability to direct higher levels of reporter gene expression. A 4.8 kb 5′-flanking region greatly increased levels of ripening-specific reporter gene activity, while a 1.8 kb 3′ region was only shown to have a positive regulatory role in the presence of the extended 5′ region. Transgenic plants containing the CAT gene flanked by both of these regions showed the same temporal pattern of accumulation of CAT and PG mRNA, and steady-state levels of the transgene mRNA were equivalent to 60% of the endogenous PG mRNA on a per gene basis. The proximal 150 bp of the PG promoter gave no detectable CAT activity. However, the distal 3.4 kb of the 4.8 kb 5′ PG promoter was shown to confer high levels of ripening-specific gene expression when placed in either orientation upstream of the 150 bp minimal promoter. The DNA sequence of the 3.4 kb region revealed a 400 bp imperfect reverse repeat, and sequences which showed similarity to functionally significant sequences from the ripening-related, ethylene-regulated tomato E8 and E4 gene promoters. The possible roles of the flanking regions in regulating PG gene expression are discussed.
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  • 66
    ISSN: 1573-5028
    Keywords: acetohydroxyacid synthase ; gene organization ; gene expression ; herbicide resistance ; cotton ; Gossypium hirsutum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The acetohydroxyacid synthase (AHAS) gene family of the cotton AD allotetraploid Gossypium hirsutum has been cloned and characterized. We have identified six different AHAS genes from an analysis of genomic clones and Southern blots of genomic DNA. Four of the six genes are organized as tandem pairs, in which the genes are separated by only 2–3 kb. Conservation of restriction fragment length polymorphisms between G. hirsutum and A-genome and D-genome-containing diploid cottons was sufficient to assign the single genes in clones A5 and A19 to the A and D subgenomes, respectively. Each diploid genome has one tandem pair, but in these cases we could not make specific subgenomic assignments. DNA and deduced amino acid sequences were determined for the A5 and A19 genes, and an AHAS cDNA clone isolated from a leaflibrary. The sequence of the A19 gene matches that of the cDNA clone, while the A5 gene is 97.8% similar. The four genes comprising the tandem pairs are much less similar to the cDNA clone. The deduced amino acid sequences of the mature polypeptides encoded by the A5 and A19 genes are collinear with the housekeeping forms of AHAS from Arabidopsis thaliana, Nicotiana tabacum and Brassica napus. The constitutive expression of A5 and A19 was confirmed with RNase protection assays and northern blots. We conclude that these genes encode the main house-keeping froms of AHAS in G. hirsutum. Among the four AHAS genes comprising the two tandem pairs, at least two are functional. These genes exhibit either low-level constitutive expression (one or both of the ‘downstream’ genes of each pair), or highly specific expression in reproductive tissue (one or both of the ‘upstream’ genes of each pair). The AHAS gene family of G. hirsutum is more complex than that of other plants so far examined.
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  • 67
    ISSN: 1573-5028
    Keywords: Brassica ; phosphate starvation ; gene expression ; β-glucosidase ; mineral nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Differential gene expression at the transcriptional level was examined as an initial step in the investigation of the Pi starvation response of Brassica nigra suspension cells. Total RNA was extracted from 7-day old cells grown in media containing either no Pi, 1.25 mM or 10 mM Pi., In vitro translation was carried out using their respective poly(A)+ RNA isolates and the resultant polypeptides were separated on a high-resolution SDS-PAGE gel. Scanning densitometry identified four polypeptides (ca. 31.7, 32.3, 52.5 and 64.8 kDa) present only in the Pi-starved samples. Screening by differential hybridization was performed on a cDNA library constructed from mRNA isolated from Pi-starved cells. Probes prepared from mRNA from Pi-deficient and Pi-sufficient cells identified a number of clones representing mRNA species that were preferentially transcribed under Pi deficiency. These phosphate starvation-responsive (psr) clones were placed into eleven groups as determined by cross-hybridization. Northern blots showed that the corresponding genes are inducible in both mild and severe Pi starvation conditions. Preliminary sequencing identified one of the clones as being homologous to β-glucosidases from several plant species. The possible role of β-glucosidase during Pi starvation and the identities of the other psr genes are discussed.
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  • 68
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    Plant molecular biology 1 (1982), S. 89-102 
    ISSN: 1573-5028
    Keywords: sorghum ; mitochondria ; cytoplasmic male sterility ; plasmids ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variation in sorghum mitochondrial translation products has enabled fertile (Kafir) cytoplasm to be distinguished from Milo cytoplasmic male sterile cytoplasm and from three alternative sources of cytoplasmic male sterile cytoplasm. Mitochondria from Milo cytoplasm synthesised a 65 000 mol. wt. polypeptide which was not synthesised by those from Kafir cytoplasm. In the cytoplasmic male sterile combination of Kafir nucleus in Milo cytoplasm synthesis of this polypeptide was dramatically increased. Mitochondria from two cytoplasmic male sterile lines (Kafir nucleus in IS1112 cytoplasm and Yellow Feterita nucleus in M35-1 cytoplasm) did not synthesise the 65 000 mol. wt. polypeptide but synthesised additional high molecular weight polypeptides (from 54 000 to 82 000 mol. wt.), the major one being 82 000. Mitochondria from cytoplasm IS1112 were also distinguished by synthesis of an additional 12 000 mol. wt. polypeptide. Mitochondria from the cytoplasmic male sterile line Martin nucleus in 9E cytoplasm synthesised an additional 42 000 mol. wt. polypeptide but did not synthesise a 38 000 mol. wt. polypeptide detected in all other cytoplasms. Immunoprecipitation of mitochondrial translation products with antiserum raised against subunit I of yeast cytochrome oxidase tentatively identified the 38 000 mol. wt. polypeptide as subunit I of sorghum cytochrome oxidase. The 42 000 mol. wt. polypeptide was also immuno-precipitated by this antiserum and thus is probably an altered form of cytochrome oxidase subunit I. Analysis of native mitochondrial DNA by agarose gel electrophoresis revealed the presence of two ‘plasmid-like’ DNA species of molecular weight 5.3 and 5.7 kb in the cytoplasmic male sterile lines Kafir nucleus in cytoplasm IS1112 and Yellow Feterita nucleus in M35-1 cytoplasm. Thus there is a positive correlation between the synthesis of the 82 000 mol. wt. polypeptide and the presence of the additional DNA species.
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  • 69
    ISSN: 1573-5028
    Keywords: linked gene ; gene expression ; peroxidase ; Populus kitakamiensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A genomic library was prepared from Populus kitakamiensis and screened with the cDNA for an anionic peroxidase from P. kitakamiensis. One genomic clone was isolated that contained two tandemly oriented genes for anionic peroxidases, prxA3a and prxA4a. Both genes consisted of four exons and three introns; the introns had consensus nucleotides, namely, GT and AG, at their 5′ and 3′ ends, respectively. The prxA3a and prxA4a genes encoded 347 and 343 amino acid residues, respectively, including putative signal sequences at the amino-termini. Putative promoters and polyadenylation signals were found in the flanking regions of both genes. The sequence of the coding region of prxA3a was completely identical to that of the cDNA clone pA3, whereas the sequence of the coding region of prxA4a was only 73% identical to that of the cDNA clone pA3. Northern blot analysis showed that the patterns of expression of the mRNAs that corresponded to prxA3a and prxA4a differed in stems of P. kitakamiensis.
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  • 70
    ISSN: 1573-5028
    Keywords: anthocyanin ; Compositae ; corolla ; dfr ; flower development ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the ornamental cut flower plant Gerbera hybrida the spatial distribution of regulatory molecules characteristic of differentiation of the composite inflorescence is visualized as the various patterns of anthocyanin pigmentation of different varieties. In order to identify genes that the plant can regulate according to these anatomical patterns, we have analysed gene expression affecting two enzymatic steps, chalcone synthase (CHS) and dihydroflavonol-4-reductase (DFR), in five gerbera varieties with spatially restricted anthocyanin pigmentation patterns. The dfr expression profiles vary at the levels of floral organ, flower type and region within corolla during inflorescence development according to the anthocyanin pigmentation of the cultivars. In contrast, chs expression, although regulated in a tissue-specific manner during inflorescence development, varies only occasionally. The variation in the dfr expression profiles between the varieties reveals spatially specific gene regulation that senses the differentiation events characteristic of the composite inflorescence.
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  • 71
    ISSN: 1573-5028
    Keywords: spinach chloroplast DNA ; gene expression ; initiation of transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thein vitro DNA- or RNA-directed synthesis of the large subunit (LS) of spinach chloroplast ribulose-1,5-biphosphate carboxylase (RuP2C) has been examined in a highly definedE. coli transcription-translation system. Spinach chloroplast DNA, RNA and recombinant plasmids containing the spinach chloroplast LS gene (rbcL) have been used as templates in thein vitro system and a quantitative assay has been developed to measure LS formation. Thein vitro formed product contains formylmethionine at the N-terminal position and sediments primarily as a monomer. There is no detectable enzymatic activity associated with thein vitro product. To determine where theE. coli RNA polymerase used in these systems initiates, we have examined the transcripts produced by this enzymein vitro. Measurements of run-off transcripts indicate thatE. coli RNA polymerase initiates at the same position on the gene as is seenin vivo. In addition, the complete nucleotide sequence of therbcL gene including previously unsequenced 3′ and 5′ flanking regions has been determined. The sequence agrees, except at two nucleotide positions, with previously published sequencing data for this gene (Zurawski, G, Perrot, B, Bottomley, W, Whitfeld, PR, 1981. Nucleic Acids Res. 9:3251–3270).
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  • 72
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    Plant molecular biology 27 (1995), S. 441-456 
    ISSN: 1573-5028
    Keywords: HSP70 ; HSC70 ; seed development ; imbibition ; chaperone ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Eukaryotes express several cytoplasmic HSP70 genes, and their encoded proteins participate in diverse cellular processes. Three cDNAs encoding highly expressed cytoplasmic HSP70 homologues from Pisum sativum were cloned and characterized. They were designated PsHSP71.2, PsHSC71.0, and PsHSP70b. These HSP70 genes have different expression profiles in leaves: PsHSP71.2 is observed only in response to heat stress, PsHSC71.0 is present constitutively, and PsHSP70b is weakly constitutively expressed, but induced strongly in response to heat stress. In addition to being heat induced, the PsHSP71.2 mRNA is also expressed in zygotic, but not maternal organs of developing pea seeds, while PsHSC71.0 and PsHSP70b mRNAs are present in maternal and zygotic organs throughout seed development. Immunoblot analysis of parallel protein samples detects a 70 kDa polypeptide in all samples, and a 72 kDa polypeptide that corresponds to the PsHSP71.2 gene product is observed in cotyledons beginning at mid-maturation and in axes beginning between late maturation and desiccation. This polypeptide is not detected in the seed coat. The 72 kDa polypeptide remains abundant in both cotyledons and axes through germination, but declines substantially between 48 and 72 h after the onset of imbibition. Differential control of HSP70 expression during heat stress, seed maturation, and germination is consistent with the hypothesis that there are functional distinctions between cytoplasmic HSP70s.
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  • 73
    ISSN: 1573-5028
    Keywords: Cucumis sativus ; gene expression ; glyoxylate cycle ; glyoxysome ; isocitrate lyase ; seed germination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cucumber (Cucumis sativus L.) genome contains only a single gene encoding the glyoxylate cycle enzyme isocitrate lyase (ICL). The cucumber icl gene has been isolated and sequenced, revealing only two small introns. The predicted amino acid sequence is more than 85% identical to ICL from other higher plants, and contains the C-terminal tripeptide Ser-Arg-Met which resembles a peroxisomal targeting sequence. The icl gene is coordinately expressed with the malate synthase (ms) gene after seed germination in both the light and the dark, suggesting that these genes may contain similar DNA elements regulating transcription. The start of transcription of the icl gene was determined and the DNA sequences upstream compared with the region of the ms gene promoter known to regulate transcription. This comparison revealed a highly conserved DNA sequence at similar positions in each gene.
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  • 74
    ISSN: 1573-5028
    Keywords: Alfalfa ; cell division cycle ; chromosomal location ; cyclin ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cyclins in association with the protein kinase p34cdc2and related cyclin-dependent protein kinases (cdks) are key regulatory elements in controlling the cell division cycle. Here, we describe the identification and characterization of a full-length cDNA clone of alfalfa mitotic cyclin, termed CycIIIMs. Computer analysis of known plant cyclin gene sequences revealed that this cyclin belongs to the same structural group as the other known partial alfalfa cyclin sequences. Genetic segregation analysis based on DNA-DNA hybridization data showed that the CycIIIMs gene(s) locates in a single chromosomal region on linkage group 5 of the alfalfa genetic map between RFLP markers UO89A and CG13. The assignment of this cyclin to the mitotic cyclin class was based on its cDNA-derived sequence and its differential expression during G2/M cell cycle phase transition of a partially synchronized alfalfa cell culture. Sequence analysis indicated common motifs with both the A- and B-types of mitotic cyclins similarly to the newly described B3-type of animal cyclins.
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  • 75
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    Plant molecular biology 29 (1995), S. 647-662 
    ISSN: 1573-5028
    Keywords: gene expression ; peroxidase ; powdery mildew ; splicing ; Triticum aestivum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A PCR-based screening approach was used to isolate genomic clones from wheat encoding peroxidase isozymes. Three complete genes (pox1, pox2 and pox4) and one truncated gene (pox3) were characterized. The nucleotide sequences predicted mature proteins of 31 kDa, in which all the highly conserved motifs of secreted plant peroxidases were preserved. The coding regions showed 73–83% DNA sequence identity, with the highest level of similarity noted for the tandemly oriented pox2 and pox3. Expression of respective pox genes in various tissues of wheat was assessed by the RT-PCR technique, which showed that all four genes are active. The primary pox1 mRNA was spliced to remove three introns, whereas processing of the other pox transcripts involved only two intervening sequences. Splicing occurred at consensus GU/AG splice sites except for the first introns of pox1, pox2 and pox4 transcripts, where processing took place at unusual GC donor sites. The RNA analysis suggested that the pox1, pox2 and pox4 genes are predominantly expressed in roots. Lower levels of expression were found for pox4 and pox3 in leaves. Infection of wheat by the powdery mildew fungus selectively induced expression of pox2 in leaves.
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  • 76
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    Plant molecular biology 29 (1995), S. 1211-1221 
    ISSN: 1573-5028
    Keywords: ferredoxin ; Citrus ; ethylene ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sequence and expression of mRNA homologous to a cDNA encoding a non-photosynthetic ferredoxin (Fd1) from Citrus fruit was investigated. The non-photosynthetic nature of this ferredoxin was deduced from: (1) amino acid sequence alignments showing better scores with non-photosynthetic than with photosynthetic ferredoxins, (2) higher expression in tissues containing plastids other than chloroplast such as petals, young fruits, roots and peel of fully coloured fruits, and (3) the absence of light-dark regulation characteristic of photosynthetic ferredoxins. In a phylogenetic tree constructed with higher-plant ferredoxins, Citrus fruit ferredoxin clustered together with root ferredoxins and separated from the photosynthetic ferredoxins. Non photosynthetic (root and fruit) ferredoxins, but not the photosynthetic ferredoxins, have their closest homologs in cyanobacteria. Analysis of ferredoxin genomic organization suggested that non-photosynthetic ferredoxins exist in Citrus as a small gene family. Expression of Fd1 is developmentally regulated during flower opening and fruit maturation, both processes may be mediated by ethylene in Citrus. Exogenous ethylene application also induced the expression of Fd1 both in flavedo and leaves. The induction of non-photosynthetic ferredoxins could be related with the demand for reducing power in non-green, but biosynthetically active, tissues.
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  • 77
    ISSN: 1573-5028
    Keywords: gene expression ; photosynthesis ; protein turnover ; psbA ; tac promoter ; D1 protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Over-expression of the psbAIII gene encoding for the D1 protein (form II; D1:2) of the photosystem II reaction centre in the Synechococcus sp. PCC 7942 was studied using a tac promoter and the lacI Q system. Over-expression was induced with 40 μg/ml IPTG in the growth medium for either 6 or 12 h at growth irradiance (50 μmol photons m-2 s-1). This treatment doubled the amount of psbAII/III mRNA and the D1:2 protein in membranes but decreased the amount of psbAI messages and the D1:1 protein. The total amount of both heterodimeric reaction centre proteins, D1 and D2, remained constant under growth light conditions, indicating that the number of PSII centres in the membranes was not affected, only the form of the D1 protein was changed from D1:1 to D1:2 in most centres. When the cells were photoinhibited either at 500 or 1000 μmol photons m-2 s-1, in the presence or absence of the protein synthesis inhibitor lincomycin, the D1:2 protein remained at a higher level in cells in which over-expression had been induced by IPTG. These cells were also less prone to photoinhibition of PSII. It is suggested that the tolerance of cells to photoinhibition increases when most PSII reaction centres contain the D1:2 protein at the beginning of high irradiance. This tolerance is further strengthened by maintaining psbAIII gene over-expression during the photoinhibitory treatment.
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  • 78
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; cDNA ; gene expression ; starch biosynthesis ; starch branching enzyme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two starch branching enzyme (SBE) cDNAs were identified in an Arabidopsis seedling hypocotyl library using maize Sbe1 and Sbe2 cDNAs as probes. The two cDNAs have diverged 5′ and 3′ ends, but encode proteins which share 90% identity over an extensive region with 70% identity to maize SBE IIb [12]. Genomic Southern blots suggest that the two cDNAs are the products of single, independent genes, and that additional, more distantly related SBE genes may exist in the Arabidopsis genome. The two cDNAs hybridize to transcripts which show similar expression patterns in Arabidopsis vegetative and reproductive tissues, including seedlings, inflorescence rachis, mature leaves, and flowers. This is the first report of the identification of cDNAs encoding two closely related starch branching enzymes from the same species.
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  • 79
    ISSN: 1573-5028
    Keywords: Agrobacterium rhizogenes ; gene expression ; GUS staining ; in situ hybridization ; rolA gene ; tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatial and temporal activity of the entire and individual promoter domains of the rolA gene of Agrobacterium rhizogenes was investigated and correlated with the distinctive features of the phenotypes of transgenic tobacco plants. The GUS assay was performed in the presence of an oxidative catalyst during the development of transgenic plants expressing chimeric genes containing the β-glucuronidase coding sequence under the control of the different promoter domains. In situ hybridization was also used on transgenic plants harbouring rolA under the control of the entire or deleted promoter. This paper demonstrates for the first time that the entire rolA promoter, composed of domains, A, B and C, is silent in seeds, then activated at the onset of germination in the cotyledons and in the elengation zone of the radicle and is finally expressed throughout the vegetative and floral phases. Domains B+C, which were sufficient to induce wrinkled leaves and short internodes, were active in all the stem tissues, but only in the companion cells of the phloem strands of the leaves. Domain C, which specified a dwarf phenotype with normal leaves, was weakly expressed in the stem vascular bundles and in the leaf internal phloem. These results indicate that the vascular bundles are the primary targets for the generation of the short internode phenotype. Furthermore, the local expression of rolA in the stem vascular bundles induced a size reduction of the surrounding parenchyma cells, suggesting the existence of some diffusible factor(s) associated with the expression of the rolA gene.
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  • 80
    ISSN: 1573-5028
    Keywords: Arabidopsis ; gene expression ; hypersensitive response ; plant-pathogen interactions ; cell suspensions ; sulfotransferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA clone (RaRO47) encoding a sulfotransferase (ST) has been isolated from Arabidopsis cell suspensions. The deduced polypeptide of 302 amino acids is highly related to plant flavonol sulfotrans-ferases (FSTs), characterized for the first time in Flaveria, and also to STs from animal tissue. The expression of the Arabidopsis ST gene(s) corresponding to RaR047 was examined during different developmental stages. It was found that, at the level of steady-state mRNA, expression of gene(s) encoding this ST was rapidly induced in the aerial parts of young seedlings, and during growth of Arabidopsis cell cultures. No expression could be detected in roots. Treatment of Arabidopsis seedlings with hormonal or stress-related compounds, showed that RaR047 mRNA accumulation was more particularly induced in response to salicylic acid and methyl jasmonate. Furthermore, in the leaves of mature plants or in cell suspensions, accumulation of RaR047 mRNA was observed upon infection with bacterial pathogens. This expression was observed preferentially in response to avirulent pathogens causing an hyper-sensitive reaction, as compared to virulent pathogens, which lead to disease.
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  • 81
    ISSN: 1573-5028
    Keywords: cDNAs ; Douglas fir ; gene expression ; germination ; low-molecular-weight heat shock proteins ; methyl jasmonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated and sequenced two cDNA clones (PM 18.2A;PM 18.2B) from Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) which encode for the low-molecular-weight heat shock proteins (LMW HSPs) of 18.2 kDa. The predicted amino acid sequences of the two Douglas fir proteins are 97.5% identical. A phylogenetic tree of class I LMW HSPs showed that the PM LMW HSPs are found within a subgroup consisting exclusively of dicot species indicating that class I LMW HSPs evolved from a common ancestor predating the divergence of gymnosperms and angiosperms. Northern blots of RNA from dry, imbibed, stratified and germinated seeds revealed a notable induction of LMW HSP transcripts during post-germination and early seedling growth. Unlike previous reports, the expression of these HSPs appears to be primarily restricted to seedlings as mRNA transcripts were detected at very low levels during seed development and desiccation. Maximum induction of LMW HSPs in seedlings occurred during heat shock treatment at 38–40°C, whereas cold shock or wounding failed to induce HSP transcripts. The transcription of HSP genes is up regulated by GA, MeJA and auxin and is down regulated by ABA. Methyl jasmonate treatment induced expression of these genes in dormant seeds of Douglas fir. The expression of class I cytoplasmic LMW HSPs in seedlings and their regulation by plant growth regulators suggests specific roles in plant development other than desiccation tolerance.
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  • 82
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    Plant molecular biology 30 (1996), S. 711-722 
    ISSN: 1573-5028
    Keywords: developmental regulation ; gene expression ; gene family ; phenylalanine ammonia-lyase ; tobacco ; wound response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phenylalanine ammonia-lyase (PAL) catalyzes the first reaction in the general phenylpropanoid pathway leading to the production of phenolic compounds with a significant range of biological functions. A PAL gene we designated gPAL1, cloned from tobacco, consists of two exons separated by an intron of 1932 bp. Exon I, 398 bp, and exon II, 1747 bp, together encode a polypeptide of 715 amino acids. A putative TATA box and polyadenylation signal are found 144 bp upstream of the initiation codon and 193 bp downstream from the stop codon, respectively. Using various parts of gPAL1 as probes, genomic Southern blots indicated the presence of a small family of PAL genes in the tobacco genome that can be divided into two distinct subfamilies, one consisting of pal1 and pal2 and another of pal3 and pal4. Comparative genomic blot analysis of progenitor species (Nicotiana tomentosiformis and N. sylvestris) indicated that each species contains one PAL gene from each of the subfamilies, suggesting that pal1 and pal3 (or pal2 and pal4) diverged prior to the evolution of N. tabacum. Expression of the PAL gene family was examined using RNA gel blots. PAL transcript levels were significantly higher in flowers and roots than in leaves and stems of mature plants. PAL transcripts accumulate differentially during flower and leaf maturation in that mRNA levels decline during flower maturation but increase during leaf maturation. In leaves, PAL transcripts rapidly accumulated after wounding.
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  • 83
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; auxin ; gene expression ; glutathione S-transferase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genes homologous to the auxin-inducible Nt103 glutathione S-transferase (GST) gene of tobacco, were isolated from a genomic library of Arabidopsis thaliana. We isolated a λ clone containing an auxin-inducible gene, At103-1a, and part of a constitutively expressed gene, At103-1b. The coding regions of the Arabidopsis genes were highly homologous to each other and to the coding region of the tobacco gene but distinct from the GST genes that have been isolated from arabidopsis thusfar. Overexpression of a cDNA clone in Escherichia coli revealed that the AT103-1A protein had GST activity.
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  • 84
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    Plant molecular biology 30 (1996), S. 863-872 
    ISSN: 1573-5028
    Keywords: gene expression ; sucrose synthase ; sugar beet (Beta vulgaris L.)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To investigate the expression pattern of sucrose synthase, a cDNA from tap roots of sugar beet (Beta vulgaris L.) was isolated using a heterologous sucrose synthase cDNA from potato. The 2762 bp long cDNA clone designated SBSS 1 encodes for a 822 amino acid polypeptide of a predicted molecular mass of 93.7 kDa. The deduced amino acid sequence of sugar beet sucrose synthase has homologies of 65–70% when compared to predicted amino acid sequences of sucrose synthases from other species. RNA blot analysis shows that SBSS1 is expressed most predominant in tap root under normal growth conditions. Cold treatment and anaerobiosis lead to an increase in the steady-state levels of SBSS 1 mRNA in leaf and root tissue. In tap root slices, sugars in various concentrations had no influence on the SBSS 1 transcript level. On the other hand, wounding resulted in a decreased transcript level.
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  • 85
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    Plant molecular biology 30 (1996), S. 913-924 
    ISSN: 1573-5028
    Keywords: catalase ; gene expression ; gene structure ; isozyme ; reactive oxygen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The maize Cat2 gene was isolated by direct cloning and PCR. The clones were mapped and sequenced. The start site of transcription was determined by primer extension. Computer analysis of the 1.6 kb Cat2 promoter sequence has revealed an obvious TATA box, two GC boxes, a putative GA response element, and several ACGT core sequences known to have diverse regulatory functions in plants. Several other protein binding motifs were also identified within 800 bp upstream from the transcriptional start site. Five introns were identified in the Cat2 coding region. All five Cat2 introns are located in exactly the same position as five of the six introns in Cat1. Two of the Cat2 introns are located in the same position as the two Cat3 introns. The identical positioning of these introns suggests an evolutionary link between all three maize catalase genes. The response of the Cat2 gene to plant growth regulators was examined. Results clearly showed that the response of Cat2 to several environmental factors are developmental stage-dependent. Thus, complex regulatory mechanisms appear to be involved in the regulation of Cat2 expression in maize.
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  • 86
    ISSN: 1573-5028
    Keywords: ethylene ; ethylene receptor ; signal transduction ; ETR1 ; tomato ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dominant mutations in the Arabidopsis ETR1 gene block the ethylene signal transduction pathway. The ETR1 gene has been cloned and sequenced. Using the ETR1 cDNA as a probe, we identified a cDNA homologue (eTAE1) from tomato. eTAE1 contains an open reading frame encoding a polypeptide of 754 amino acid residues. The nucleic acid sequence for the coding sequence in eTAE1 is 74% identical to that for ETR1, and the deduced amino acid sequence is 81% identical and 90% similar. Genomic Southern blot analysis indicates that three or more ETR1 homologues exist in tomato. RNA blots show that eTAE1 mRNA is constitutively expressed in all the tissues examined, and its accumulation in leaf abscission zones was unaffected by ethylene, silver ions (an inhibitor of ethylene action) or auxin.
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  • 87
    ISSN: 1573-5028
    Keywords: elongation growth ; gene expression ; Hordeum vulgare ; protochlorophyllide oxidoreductase ; slender mutant ; tonoplast intrinsic protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three cDNA clones have been isolated on the basis of altered patterns of expression in the leaf extension zone of the developmental mutant,slender barley, compared with the wild type. mRNAs corresponding to two of the cDNAs, 7s and 8s, are increased inslender compared with normal. 7s encodes a putative γ-TIP and is expressed throughout the elongation zone. γ-TIPs form transmembrane channels which allow the passive transfer of water. Although expression of 7s was increased inslender leaf tissue, the increase was much less extreme than that shown by Phillips and Huttly (1994) following the application of GA to an extreme dwarf ofArabidopsis. 8s is maximally expressed in the region of early cell elongation and has 66% encoded protein identity with MFS18, a cDNA encoding a putative cell wall structural protein isolated from male flowers of maize. Both 8s and MFS18 encode small (128 amino acids) basic proteins rich in glycine, alanine, proline and serine. mRNA corresponding to the third cDNA, 24n, is present at a greatly reduced level inslender compared with normal and encodes protochlorophyllide oxidoreductase (POR). POR catalyses the conversion of protochlorophyllide into chlorophyllide. The reduced level of POR mRNA is not correlated with a similar reduction in expanded leaf blade chlorophyll levels. Western analysis identified two POR proteins present in light-grown seedlings. Whilst the larger of the proteins is present throughout most of the leaf, the smaller protein mimics the mRNA results, being both maximally present in the elongation tissue and present at a reduced level inslender. An antagonistic relationship between chlorophyll biosynthesis and extension growth is suggested.
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  • 88
    ISSN: 1573-5028
    Keywords: Chlamydomonas reinhardtii ; chlorophyll a/b-binding protein gene ; circadian rhythms ; gene expression ; light-regulated genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the green unicellular alga Chlamydomonas reinhardtii, as in higher plants, the expression of the genes encoding the chlorophyll a/b-binding (CAB) polypeptides associated with photosystem I (PSI) and photosystem II (PSII) is regulated by endogenous (circadian clock) and exogenous signals (light and temperature). The circadian clock ensures that the oscillation in the levels of the different cab mRNAs is continuously kept in phase with light/dark (LD) cycles and is maximal by the middle of the day. On the other hand, light controls the amplitude of the oscillations. We report here the cloning and characterization of the C. reinhardtii LI818 gene, which identifies a CAB-related polypeptide and whose expression is regulated quite differently from the cabI/II genes. We show: (1) that in LD synchronized Chlamydomonas cells LI818 mRNA accumulation is subject to dual regulation that involves separable regulation by light and an endogenous oscillator; (2) that LI818 mRNA is fully expressed several hours before the cab I/II mRNAs and that the latter accumulate concomitantly; (3) that blocking the electron flow through PSII using DCMU prevents cells from accumulating cab I/II mRNAs but not LI818 mRNA and (4) that the accumulation of LI818 mRNA is abolished by blocking cytoplasmic protein synthesis, suggesting that these regulatory mechanisms are mediated by labile proteins.
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  • 89
    ISSN: 1573-5028
    Keywords: gene expression ; Glycine max. L. ; nodule development ; purN ; purD ; GAR synthetase ; GAR transformylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Soybean nodule cDNA clones encoding glycinamide ribonucleotide (GAR) synthetase (GMpurD) and GAR transformylase (GMpurN) were isolated by complementation of corresponding Escherichia coli mutants. GAR synthetase and GAR transformylase catalyse the second and the third steps in the de novo purine biosynthesis pathway, respectively. One class of GAR synthetase and three classes of GAR transformylase cDNA clones were identified. Northern blot analysis clearly shows that these purine biosynthetic genes are highly expressed in young and mature nodules but weakly expressed in roots and leaves. Expression levels of GMpurD and GMpurN mRNAs were not enhanced when ammonia was provided to non-nodulated roots.
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  • 90
    ISSN: 1573-5028
    Keywords: cell division cycle ; gene expression ; mitotic cyclin ; plant suc1 homologue ; Ntcdc2-1 ; Nicotiana tabacum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have previously reported the isolation of a cDNA encoding a mitotic cyclin, NTCYC1, from a tobacco cell suspension library. Here we describe the expression patterns of NTCYC1 and of Ntsuc1, a suc1 plant homologue, in synchronized tobacco cell suspensions. Furthermore, the expression pattern of this cyclin is compared to that of Ntcdc2-1, a Nicotiana tabacum homologue of cdc2. While no NTCYC1 transcript was detected in cells synchronized in the G1 and S phases, NTCYC1 expression was observed in late G2 and early M phases, disappearing in the G1′ of a new cell cycle. On the other hand, Ntsuc1 and Ntcdc2-1 exhibited a constitutive expression during the cell cycle. A functional analysis performed by microinjecting NTCYC1 mRNA into immature Xenopus oocytes, indicates that NTCYC1 could participate in the control of the G2/M transition in plant cells. Subsequently NTCYC1 expression was used to assess the status of mesophyll cells in expanded leaves of N. tabacum. Depending on leaf position along the shoot axis, a large population of mesophyll cells appeared with a 4C DNA content, suggesting a G2 arrest. It was found that leaves with such a population also contained high levels of NTCYC1 transcripts. With respect to these results concerning a naturally occurring G2-arrested cell population, the regulation of NTCYC1 expression in planta is discussed.
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  • 91
    ISSN: 1573-5028
    Keywords: cDNA cloning ; ethylene ; fruit ripening ; gene expression ; melon ; wounding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In vitro translation of mRNAs and polyacrylamide gel electrophoresis of proteins from melons revealed that several mRNAs increased in amount during ripening, indicating the existence of other ripening genes in addition to those cloned previously. To identify ripening-related genes we have screened a ripe melon cDNA library and isolated two novel cDNA clones (MEL2 and MEL7) encoding unidentified proteins. Southern analysis revealed that MEL2 and MEL7 are encoded by low-copy-number genes. The MEL2 cDNA clone is near full-length, corresponds to a 1600 nucleotide mRNA that accumulates during ripening and encodes a predicted protein rich in hydrophobic amino acids. The MEL7 cDNA clone is full-length, corresponds to a mRNA of 0.7 kb which accumulates during early ripening stages and is also present at low levels in other organs of the melon plant. The MEL7 predicted polypeptide is 17 kDa and shows significant homology with the major latex protein from opium-poppy. Wounding and ethylene treatment of unripe melon fruits 20 days after anthesis showed that MEL2 and MEL7 mRNAs are only induced by ethylene.
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  • 92
    ISSN: 1573-5028
    Keywords: gene expression ; heat shock ; oxidative stress ; ozone ; pathogenesis-related protein ; Petroselinum crispum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Parsley (Petroselinum crispum L.) is known to respond to pathogen attack by the synthesis of furanocoumarins and to UV irradiation by the synthesis of flavone glycosides whereas ozone treatment results in the induction of both pathways. A cDNA library from parsley plants was differentially screened using labelled reverse-transcribed poly(A)+ RNA isolated from ozone-treated parsley plants. This resulted in the isolation of 13 independent cDNA clones representing ozone-induced genes and of 11 cDNA clones representing ozone-repressed genes. DNA sequencing of several clones resulted in the identification of pathogenesis-related protein 1-3 (PR1-3), of a new member of PR1 cDNAs (PR1-4) and of a small heat shock protein (sHSP). Northern blot analyses showed a transient induction of the three mRNA species after ozone fumigation. In contrast, heat shock treatment of parsley plants resulted in an increase of sHSP mRNA whereas no increase for transcripts of PR1-3 and PR1-4 could be observed. This is the first characterized sHSP cDNA clone for plants induced by heat shock, as well as by oxidative stress caused by ozone.
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  • 93
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    Plant molecular biology 33 (1997), S. 301-311 
    ISSN: 1573-5028
    Keywords: asparagine ; asparagine synthetase ; cDNA clone ; complementation ; gene expression ; Glycine max
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two cDNA clones (SAS1 and SAS2) encoding different isoforms of asparagine synthetase (AS; EC 6.3.5.4) were isolated. Their DNA sequences were determined and compared. The amino-terminal residues of the predicted SAS1 and SAS2 proteins were identical to those of the glutamine binding domain of AS from pea, asparagus, Arabidopsis and human, suggesting that SAS1 and SAS2 cDNAs encode the glutamine-dependent form of AS. The open reading frames of SAS1 and SAS2 encode a protein of 579 and 581 amino acids with predicted molecular weights of 65 182 and 65 608 Da respectively. Similarity of the deduced amino acid sequences of SAS1 and SAS2 with other known AS sequences were 92% and 93% for pea AS1; 91% and 96% for pea AS2; 88% and 91% for asparagus; 88% and 90.5% for Arabidopsis; 70.5% and 72.5% for E. coli asnB and 61% and 63% for man. A plasmid, pSAS2E, was constructed to express the soybean AS protein in Escherichia coli. Complementation experiments revealed that the soybean AS protein was functional in E. coli. Southern blot analysis indicated that the soybean AS is part of a small gene family. AS transcript was expressed in all tissues examined, but higher levels were seen in stem and root of light-grown tissue and leaves of dark-treated tissue.
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  • 94
    ISSN: 1573-5028
    Keywords: in vivo protein synthesis ; gene expression ; germination ; isocitrate lyase ; isoform ; megagametophyte ; Pinus taeda L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two full-length cDNAs encoding the glyoxysomal enzyme isocitrate lyase(ICL) were isolated from a λZAP cDNA library prepared frommegagametophyte mRNAs extracted from seeds imbibed at 30 °C for 8days. The cDNAs, designated Ptbs ICL 8 and Ptbs ICL 12, have openreading frames of 1740 and 1719 bp, with deduced amino acid sequences of580 and 573 residues, respectively. The predicted amino acid sequencesof Ptbs ICL 8 and Ptbs ICL 12 exhibit a 79% identity with each other,and have a greater than 75% identity with ICLs from variousangiosperm species. The C-termini of Ptbs ICL 8 and Ptbs ICL 12terminate with the tripeptide Ser-Arg-Met and Ala-Arg-Met, respectively,both being conserved variants of the type 1 peroxisomal targetingsignal. RNA blot and slot analysis revealed that Ptbs ICL 8 and PtbsICL 12 mRNAs were present at low levels in the megagametophyte of themature and stratified seeds, and that the level of both transcriptsincreased markedly upon seed germination. Protein blot analysisindicated that the steady-state level of ICL was low in the mature andstratified seed, then increased rapidly upon seed germination, peakingat around 8-10 days after imbibition (DAI). Changes in the level ofICL activity in cell-free extracts was similar to the steady-stateprotein content with the exception that ICL activity was not detected inmegagametophyte extracts of mature or stratified seeds. From 10-12 DAIwhen the megagametophyte tissue senesced, ICL activity decreased rapidlyto near undetectable levels. In contrast, steady-state levels of ICLprotein and mRNA remained relatively constant during megagametophytesenescence. In vivo synthesis of ICL protein was measured to shedlight on these differences. ICL immunoselected from[35S]-methionine labelled proteins indicated that ICL wassynthesized at very low levels during megagametophyte senescence.Together, the results show that loblolly pine ICL gene expression iscomplex. While temporal regulation appears to be primarilytranscriptional, it also involves a number of post-transcriptionalprocesses including at least one translational and/or post-translationalmechanism.
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  • 95
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    Plant molecular biology 34 (1997), S. 345-352 
    ISSN: 1573-5028
    Keywords: heat shock ; pea (Pisum sativum L.) ; gene expression ; pod lignification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A pea pod cDNA library was screened for sequences specific to lignifying tissue. A cDNA clone (pLP19) encoding the C-terminal region of a hsp70 heat shock protein hybridised only to pod mRNA from pea lines where pod lignification occurred. Expression of pLP19 was induced by heat shock in leaves, stems and roots of pea and chickpea plants. Four different poly(A) addition sites were observed in cDNAs derived from the same gene as pLP19. This gene was fully sequenced; unlike most hsp70 genes, it contains no introns. The 5′-flanking sequence contains heat shock elements and other potential regulatory sequences.
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  • 96
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    Plant molecular biology 33 (1997), S. 821-834 
    ISSN: 1573-5028
    Keywords: leaf senescence ; genes ; gene expression ; subtractive hybridisation ; Brassica napus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A subtractive hybridisation technique was developed to clone cDNAs representing genes that showed enhanced expression during leaf senescence in Brassica napus. A number of different genes were identified that, when analysed by northern hybridisation, showed different patterns of expression during leaf development but were all expressed at increased levels during senescence. Sequence analysis of these cDNAs showed that several types of genes were found including two different proteases, glutamine synthetase, ATP sulphurylase, catalase, metallothionein, ferritin and an antifungal protein. The possible roles of these gene products in the senescence process are discussed.
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  • 97
    ISSN: 1573-5028
    Keywords: gene expression ; grass ; Phalaris ; self-incompatibility ; thioredoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Self-incompatibility is widespread in the grasses and it is proposed that the grasses share a common incompatibility mechanism that is distinct from those operating in the dicotyledonous species studied in great detail. Where good genetic data are available, all grass species appear to have an incompatibility mechanism controlled by two unlinked loci, S and Z. A putative S gene has been cloned from Phalaris coerulescens. This gene is characterized by two major domains: an allele specificity domain and a thioredoxin catalytic domain. A family of sequences with varying degrees of homology to this gene has been identified among 15 grass species covering all subfamilies of the Poaceae. These S-related sequences appear to be present in the grass family regardless of self-compatibility. Evidence is presented to show that at least one of the sequences is transcribed, suggesting a functional gene. In contrast to the high expression of the S gene in Phalaris pollen, expression of the related gene in the pollen (or anthers) of the grass species examined was so low that RNA gel blot analysis failed to display a significant signal. However, reverse transcription-based polymerase chain reaction (RT-PCR) successfully amplified the region corresponding to the S thioredoxin domain from 10 of the grass species. With grasses other than Phalaris, RT-PCR showed limited success in amplifying the region corresponding to the S variable portion at the 5′ end of the Phalaris S gene. Sequencing of the PCR-amplified S thioredoxin region from wheat, barley, rye and Dactylis revealed that this is a highly conserved gene with 94–97% sequence similarity with the corresponding Phalaris S gene. The conservation of sequence and ubiquitous expression of the gene across the grass family strongly suggest that the S-related gene is carrying out a significant biological function in the Poaceae. On the basis of these findings, a model for the evolution of the S self-incompatibility gene in the grasses is proposed.
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  • 98
    ISSN: 1573-5028
    Keywords: chloroplast-derived trnH ; chloroplast genome ; DNA transfer ; gene expression ; Gramineae ; mitochondrial genome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We reported previously that the mitochondrial sequence that contains the chloroplast-derived trnH gene has been highly conserved in the region around one terminus of the junction between chloroplast-derived and mitochondrion-specific sequences in most of the gramineous plants analyzed [15]. The results of RT-PCR, northern hybridization, in vitro capping and ribonuclease protection experiments show that the chloroplast-derived trnH gene is transcribed from a putative promoter that is located in the mitochondrion-specific sequence. Gene expression in this region seems to be correlated with the conservation of the sequence at the junction between the chloroplast-derived fragment and the mitochondrion-specific sequence.
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  • 99
    ISSN: 1573-5028
    Keywords: Bacillus thuringiensis ; coleoptera ; eggplant ; gene expression ; insect resistance ; Solanum integrifolium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Solanum melongena (eggplant) cv. Picentia and the wild species Solanum integrifolium were transformed with both a wild type (wt) and four mutagenized versions of Bacillus thuringiensis (Bt) gene Bt43 belonging to the cry3 class. The Bt gene was partly modified in its nucleotide sequence by replacing four target regions (W: +1 to +170; X: +592 to+1057 ; Y: +1203 to +1376; Z: +1376 to +1984) with synthetic fragments obtained by polymerase chain reaction amplification of crude oligonucleotides. The synthetic Bt genes were designed to avoid, in their modified regions, sequences such as ATTTA sequence, polyadenylation sequences and splicing sites, which might destabilize the messenger RNA. Furthermore, the codon usage was improved for a better expression in the plant system. The amino acid composition was not altered. Four versions of the modified Bt gene were obtained, BtE, BtF, BtH and BtI, with a nucleotide subtitution percentage of 8.2, 8.6, 14, and 16%, respectively, in comparison to the wt gene Bt43. Modified versions contained different subsets of substituted regions: BtE - W+Z, BtF - Y+Z, BtH - X+Y+Z, BtI - W+X+Y+Z. In the final modified version (BtI), overall guanine + cytosine was increased from the 34.1% of the wt gene to 45.5%, and most of the destabilizing sequences were eliminated. Transgenic plants obtained with the more modified versions, BtH and BtI, were fully resistant to Leptinotarsa decemlineata Say first- and third- instar larvae, while Bt43 wt, BtE and BtF genotypes did not cause mortality and did not affect larval development.
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  • 100
    ISSN: 1573-4978
    Keywords: MAR ; SCS ; insulation ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The flanking sequences of several genes have been shown to direct a position independent expression of transgenes. Attempts to completely identify the insulating sequences have failed so far. Some of these sequences contain a matrix attached region (MAR) located in the flanking part of the genes. This article will show that the MARs in cultured cells located in the 3' OH region of the human apolipoprotein B100 (Apo B100) and within the SV40 genome were unable to stimulate and insulate transgene expression directed by the promoters from a rabbit whey acidic protein (WAP) gene or from human cytomegalovirus (hCMV) early genes. In transgenic mice, the MAR from the Apo B100 and SV40 genes did not enhance the expression of a transgene containing the rabbit whey acid protein (WAP) promotor, the late gene SV40 intron (VP1 intron), the bovine growth hormone (bGH) cDNA and the SV40 late gene terminator. This construct was even toxic for embryos. Similarly, the specialized chromatin structure (SCS) from the Drosophila 87A7 HSP70 gene reduced chloramphenicol acetyl transferase (CAT) activity when added between a cytomegalovirus (CMV) enhancer and a Herpes simplex thymidine kinase (TK) gene promoter. This inhibitory action was almost complete when a second SCS sequence was added before the CMV enhancer. Sequences from the firefly luciferase and from the human gene cathepsin D cDNA used as control unexpectedly showed a similar inhibitory effect when added to the CMVTKCAT construct instead of SCS. When added before the CMV enhancer and after the transcription terminator in the CMVTKCAT construct, the SCS sequence was unable to insulate the integrated gene as seen by the fact that the level of CAT in cell extracts were by no means correlated with the number of copies in individual clones. From these data, it is concluded that i) a MAR containing the canonical AT rich sequences does not amplify the expression of all gene constructs ii) AT rich MAR sequences do not have per se an insulating effect iii) Drosophila SCS from the 87A7 HSP70 gene has no insulating effect in all gene constructs (at least in mammalian cells) iv) and the addition of a DNA fragment between an enhancer and a promoter in a gene construct cannot be used as a reliable test to evaluate its insulating property.
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