ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Plant Physiology and Plant Molecular Biology 52 (2001), S. 785-816 
    ISSN: 1040-2519
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Notes: Abstract Ribosome-inactivating proteins (RIPs) are toxic N-glycosidases that depurinate the universally conserved alpha-sarcin loop of large rRNAs. This depurination inactivates the ribosome, thereby blocking its further participation in protein synthesis. RIPs are widely distributed among different plant genera and within a variety of different tissues. Recent work has shown that enzymatic activity of at least some RIPs is not limited to site-specific action on the large rRNAs of ribosomes but extends to depurination and even nucleic acid scission of other targets. Characterization of the physiological effects of RIPs on mammalian cells has implicated apoptotic pathways. For plants, RIPs have been linked to defense by antiviral, antifungal, and insecticidal properties demonstrated in vitro and in transgenic plants. How these effects are brought about, however, remains unresolved. At the least, these results, together with others summarized here, point to a complex biological role. With genetic, genomic, molecular, and structural tools now available for integrating different experimental approaches, we should further our understanding of these multifunctional proteins and their physiological functions in plants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-5028
    Keywords: maize gene expression ; protoplasts ; transient assays ; transcriptional regulation ; zein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three DNA regions required for high levels of transcription were identified by transient gene expression analysis of the 5′ flanking region of a 19 kDa α-zein gene. For these analyses, the zein promoter region was fused to the β-glucuronidase (GUS) gene and assayed by transient expression in carrot protoplasts. A 107-bp sequence (-114/-8) containing the TATA box resulted in low levels of GUS activity. Addition of the proximal 75 bp (-189/-114) doubled the level of GUS expression, and a further increase in expression was obtained when additional upstream sequences (-483/-226) were placed 5′ of the zein promoters. Zein upstream sequences enhanced transcription independently of the-189/-114 region. Although the-189/-114 region was not essential for transcription, it was important to obtain maximum GUS activity. A 121 bp upstream sequence (-347/-226) that contains the conserved TGTAAAG sequence gave high levels of GUS activity when placed in either orientation 5′ of the zein promoter sequences. However, nucleotides-347 to-309, containing the TGTAAAG sequence, could be deleted from this fragment without a significant change in GUS activity. Zein upstream sequences did not promote transcription of the GUS gene in somatic maize protoplasts. The upstream activating sequence from the cauliflower mosaic virus (CaMV) 35S promoter placed 5′ of deletion mutants of the zein promoter also failed to produce GUS activity above background.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 7 (1986), S. 71-79 
    ISSN: 1573-5028
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A maize genomic clone containing a 15 kilodalton zein gene was used as a template in an in vitro transcription system for HeLa cells. A runoff assay indicated transcription was initiating 5′ to the map position of the open reading frame for the protein. Fine-structure mapping of RNAs synthesized in vitro showed two transcription start sites separated by 24 bases. One start site is 27 bases downstream of a consensus TATA sequence; the other is 30 bases downstream of a TATG sequences. The initiation sites for RNA synthesized in vitro map to the same region of the genomic clone as zein RNA isolated from developing maize kernels.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 32 (1996), S. 191-222 
    ISSN: 1573-5028
    Keywords: heat shock proteins ; foldases ; BiP ; protein transport ; protein disulfide isomerase ; calnexin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Protein folding in vivo is mediated by an array of proteins that act either as ‘foldases’ or ‘molecular chaperones’. Foldases include protein disulfide isomerase and peptidyl prolyl isomerase, which catalyze the rearrangement of disulfide bonds or isomerization of peptide bonds around Pro residues, respectively. Molecular chaperones are a diverse group of proteins, but they share the property that they bind substrate proteins that are in unstable, non-native structural states. The best understood chaperone systems are HSP70/DnaK and HSP60/GroE, but considerable data support a chaperone role for other proteins, including HSP100, HSP90, small HSPs and calnexin. Recent research indicates that many, if not all, cellular proteins interact with chaperones and/or foldases during their lifetime in the cell. Different chaperone and foldase systems are required for synthesis, targeting, maturation and degradation of proteins in all cellular compartments. Thus, these diverse proteins affect an exceptionally broad array of cellular processes required for both normal cell function and survival of stress conditions. This review summarizes our current understanding of how these proteins function in plants, with a major focus on those systems where the most detailed mechanistic data are available, or where features of the chaperone/foldase system or substrate proteins are unique to plants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1572-9788
    Keywords: transgenic rice ; bar ; b-32 ; proteolytic processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We have previously transformed rice (Oyrza sativa L.) with the maize ribosome-inactivating protein b-32 gene (Zmcrip3a) and the phosphinothricin resistance gene (bar). In the present study, Southern blot hybridization analysis of 56 primary fertile transformants resulted in distinct band patterns, indicating that all the transformants had been generated by independent integration events and 30% of them contained a single copy of the transgene. Segregation analysis of 15 R0 plants revealed that transgene was stably transmitted to their progenies and Southern blot band patterns of R1 progenies remained the same as the corresponding parents, suggesting that all the loci of multiple integration events are genetically linked. Also, in most of the lines, physical presence of the b-32 transgene co-segregated with the phosphinothricin- resistant phenotype, confirming that the transgene is behaving as a normal locus in the genome. However, some of R1 seedlings that contained multiple copies of the transgene became sensitive to phosphinothricin, indicating that its expression was silenced. Immunoblot analysis demonstrated that b-32 protein was produced and the levels of expression differed in different lines, estimated to be 0.5–1% of total soluble protein in the leaf tissues. In addition, the transgene-encoded protein was preferentially processed in germinating seeds and young leaves of R2 transgenic plants in a way similar to that in maize kernels, suggesting that the processing mechanism is conserved in the germination stage between rice and maize.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1615-6102
    Keywords: Endosperm ; Zea mays ; Immunolocalization ; Rough endoplasmic reticulum ; Binding protein ; Protein bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A maize 75 kDa protein recently has been identified as a plant homolog of the mammalian binding protein (BiP). To better understand the function of BiP in protein body formation in maize endosperm, immunomicroscopy studies were conducted on three maize endosperm mutants, floury-2, Mucronate, and Defective endosperm-B 30, in which the level of BiP is highly elevated. Our results showed that protein body morphology in all three mutants was altered. In addition, BiP was localized in both the ER and peripheral regions of the abnormal protein bodies. The degree to which protein body morphology differed from normal was positively correlated with increased amounts of BiP. In addition, the accumulation of BiP in abnormal protein bodies increased with protein body maturation. In the three endosperm mutants, the arrangement of zeins within protein bodies had been perturbed, yet none of the specific zein subclasses exhibited the staining pattern found for BiP. The association of BiP with abnormal packaging of proteins in protein bodies may reflect a biological function to mediate protein folding and assembly in maize endosperm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 207 (1987), S. 90-98 
    ISSN: 1617-4623
    Keywords: Zein ; Genomic sequence ; Gene family ; Gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleotide sequence of gz19ab11, a clone that corresponds to the coding and flanking sequences of an Mr 19000 alpha zein, was determined. Comparison of the DNA sequences flanking this gene with those of other members of the gene subfamily showed that sequence conservation extends 820 nucleotides into the 5′ flanking region and 130 nucleotides into the 3′ flanking region. Southern blot analysis of maize DNA indicated that highly repetitive sequences are located within 950 bp 5′ and 300 bp 3′ to the protein coding region of these genes. The coding region of gz19ab11 is similar to but not identical with cDNA clones corresponding to Mr 19000 zeins, and analysis of zein transcripts indicated that this gene is expressed exclusively in endosperm tissue. RNAs which correspond to transcripts originating 60 nucleotides, and more than 800 nucleotides, upstream of the initiation codon were detected for this and a related gene. However, the concentration of the large RNA species was several orders of magnitude less than that of the shorter RNAs. The functional significance of these large RNA transcripts in zein gene expression is unclear.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1617-4623
    Keywords: Zein ; Transcriptional regulation ; Electroporation ; Enhancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analysis of a series of clones containing deletions in the 5′ noncoding sequence of a gene encoding an Mr 19 000 zein allowed identification of a region required for maximal transcription. Transcriptional activity was assayed in two heterologous plant systems. In one system, the Ti plasmid was used to introduce the modified zein genes into the sunflower genome. In the other system, electroporation was used to transform carrot protoplasts with plasmids containing the zein genes. For the electrophoration experiments, the 5′ noncoding sequences from the zein clones were linked to the protein coding sequence of chloramphenicol acetyl transferase. The results showed that an upstream sequence, delimited by nucleotides-337 and-125 with respect to the mRNA cap site, is required for maximal transcription of the gene. In contrast, very low levels of transcription were directed by constructs that contained 125 bp of 5′ noncoding sequence that included the CAAT and TATA boxes, suggesting that the additional sequences (-337 to-125) further 5′ exert a quantitative effect on transcription. Examination of the additional 5′ sequences showed five regions that share homology with the SV40 enhancer core sequence.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2003-06-01
    Print ISSN: 0021-8561
    Electronic ISSN: 1520-5118
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 1998-09-01
    Print ISSN: 0021-8561
    Electronic ISSN: 1520-5118
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...