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  • 1
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cell cycle and growth control of the DNA binding and transactivation functions of regulatory factors provides a direct mechanism by which cells may coordinate transcription of a multitude of genes in proliferating cells. The promoters of human DNA replication dependent histone H4, H3, and H1 genes interact with at least seven distinct proteins. One of these proteins is a proliferation-specific nuclear factor, HiNF-D, that interacts with a key cis-regulatory element (H4-Site II; 41 bp) present in H4 genes. Here we describe binding sites for HiNF-D in the promoters of H3 and H1 genes using cross-competition, deletion analysis, and methylation interference assays, and we show that HiNF-D recognizes intricate arrangements of at least two sequence elements (CA- and AG-motifs). These recognition motifs are irregularly dispersed and distantly positioned in the proximal promoters (200 bp) of both the H3 and H1 genes. In all cases, these motifs either overlap or are in close proximity to other established transcriptional elements, including ATF and CCAAT sequences. Although HiNF-D can interact with low affinity to a core recognition domain, auxiliary elements in both the distal and proximal portions of each promoter cooperatively enhance HiNF-D binding. Thus, HiNF-D appears to bridge remote regulatory regions, which may juxtapose additional trans-activating proteins interacting within histone gene promoters. Consistent with observations in many cell culture systems, the interactions of HiNF-D with the H4, H3, and H1 promoters are modulated in parallel during the cessation of proliferation in both osteosarcoma cells and normal diploid osteoblasts, and these events occur in conjunction with concerted changes in histone gene expression. Thus, HiNF-D represents a candidate participant in coordinating transcriptional control of several histone gene classes. © 1994 wiley-Liss, Inc.
    Additional Material: 13 Ill.
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  • 4
    ISSN: 0730-2312
    Keywords: nucleus ; gene expression ; cell growth ; osteoblast ; nucleosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: During the past several years it has become increasingly evident that the three-dimensional organization of the nucleus plays a critical role in transcriptional control. The principal theme of this prospect will be the contribution of nuclear structure to the regulation of gene expression as functionally related to development and maintenance of the osteoblast phenotype during establishment of bone tissue-like organization. The contributions of nuclear structure as it regulates and is regulated by the progressive developmental expression of cell growth and bone cell related genes will be examined. We will consider signalling mechanisms that integrate the complex and interdependent responsiveness to physiological mediators of osteoblast proliferation and differentiation. The focus will be on the involvement of the nuclear matrix, chromatin structure, and nucleosome organization in transcriptional control of cell growth and bone cell related genes. Findings are presented which are consistent with involvement of nuclear structure in gene regulatory mechanisms which support osteoblast differentiation by addressing four principal questions: (1) Does the representation of nuclear matrix proteins reflect the developmental stage-specific requirements for modifications in transcription during osteoblast differentiation? (2) Are developmental stage-specific transcription factors components of nuclear matrix proteins? (3) Can the nuclear matrix facilitate interrelationships between physiological regulatory signals that control transcription and the integration of activities of multiple promoter regulatory elements? (4) Are alterations in gene expression and cell phenotypic properties in transformed osteoblasts and osteosarcoma cells reflected by modifications in nuclear matrix proteins? There is a striking representation of nuclear matrix proteins unique to cells, tissues as well as developmental stages of differentiation, and tissue organization. Together with selective association of regulatory molecules with the nuclear matrix in a growth and differentiation-specific manner, there is a potential for application of nuclear matrix proteins in tumor diagnosis, assessment of tumor progression, and prognosis of therapies where properties of the transformed state of cells is modified. It is realistic to consider the utilization of nuclear matrix proteins for targeting regions of cell nuclei and specific genomic domains on the basis of developmental phenotypic properties or tissue pathology. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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  • 5
    ISSN: 0730-2312
    Keywords: osteosarcoma cells ; osteocalcin gene ; osteoblasts ; vitamin D response element (VDRE) ; transcription factor complexes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Vitamin D responsive transcription of the bone-specific osteocalcin gene differs markedly in osteosarcoma cells and normal diploid osteoblasts. In osteoblasts the osteocalcin gene is transcribed, and upregulated by Vitamin D, only in post-proliferative cells, but in osteosarcoma cells expression is constitutive. This distinction in transcriptional regulation of the osteocalcin gene correlates with striking differences in the relative representation of two principal Vitamin D-dependent protein/DNA complexes designated V1 and V2 at the Vitamin D responsive element in the osteocalcin promoter. Formation of both complexes is Vitamin D dependent and they contain the Vitamin D receptor as well as an RXR related protein. Pore size exclusion and sedimentation velocity analyses suggest that the V1 and V2 complexes represent oligomeric protein assemblies (respectively, tetramers and trimers), and reflect primarily DNA-directed association of the monomeric protein components at the osteocalcin Vitamin D responsive element. UV crosslinking and methylation interference analyses of the V1 and V2 complexes at the osteocalcin Vitamin D responsive element indicate differences in protein/DNA recognition. For example, the V1 complex interacts with both steroid half-elements, whereas the V2 complex appears to recognize the proximal half-element. Our findings suggest variations in protein/protein and protein/DNA interactions of the VDR and RXR related complexes V1 and V2 at the osteocalcin Vitamin D responsive element that reflect unique properties of the osteosarcoma and normal diploid osteoblast phenotype. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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  • 6
    ISSN: 0730-2312
    Keywords: phosphorylation ; cell cycle ; proliferation ; transcription ; histone ; development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Cell cycle regulated gene expression was studied by analyzing protein/DNA interactions occurring at the H4-Site II transcriptional element of H4 histone genes using several approaches. We show that this key proximal promoter element interacts with at least three distinct sequence-specific DNA binding activities, designated HiNF-D, HiNF-M, and HiNF-P. HiNF-D binds to an extended series of nucleotides, whereas HiNF-M and HiNF-P recognize sequences internal to the HiNF-D binding domain. Gel retardation assays show that HiNF-D and HiNF-M each are represented by two distinct protein/DNA complexes involving the same DNA binding activity. These results suggest that these factors are subject to post-translational modifications. Dephosphorylation experiments in vitro suggest that both electrophoretic mobility and DNA binding activities of HiNF-D and HiNF-M are sensitive to phosphatase activity. We deduce that these factors may require a basal level of phosphorylation for sequence specific binding to H4-Site II and may represent phosphoproteins occurring in putative hyper- and hypo-phosphorylated forms. Based on dramatic fluctuations in the ratio of the two distinct HiNF-D species both during hepatic development and the cell cycle in normal diploid cells, we postulate that this modification of HiNF-D is related to the cell cycle. However, in several tumor-derived and transformed cell types the putative hyperphosphorylated form of HiNF-D is constitutively present. These data suggest that deregulation of a phosphatase-sensitive post-translational modification required for HiNF-D binding is a molecular event that reflects abrogation of a mechanism controlling cell proliferation. Thus, phosphorylation and dephosphosphorylation of histone promoter factors may provide a basis for modulation of protein/DNA interactions and H4 histone gene transcription during the cell cycle and at the onset of quiescence and differentiation.
    Additional Material: 7 Ill.
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  • 7
    ISSN: 0730-2312
    Keywords: CCAAT box ; osteocalcin promoter ; histone promoter ; regulatory elements ; vitamin D gene regulation ; hormone control ; transcription factors ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Several lines of evidence are presented which support involvement of the nuclear matrix in regulating the transcription of two genes, histone and osteocalcin, that are reciprocally expressed during development of the osteoblast phenotype. In the 5′ regulatory region of an H4 histone gene, which is expressed in proliferating osteoblasts early during the developmental/differentiation sequence, a dual role is proposed for the nuclear matrix binding domain designated NMP-1 (-589 to -730 upstream from the transcription start site). In addition to functioning as a nuclear matrix attachment site, the sequences contribute to the upregulation of histone gene transcription, potentially facilitated by concentration and localization of an 84kD ATF DNA binding protein. A homologous nuclear matrix binding domain was identified in the promoter of the osteocalcin gene, which is expressed in mature osteoblasts in an extracellular matrix undergoing mineralization. The NMP binding domain in the osteocalcin gene promoter resides contiguous to the vitamin D responsive element. Together with gene and transcription factor localization, a model is proposed whereby nuclear matrix-associated structural constraints on conformation of the osteocalcin gene promoter facilitates vitamin D responsiveness mediated by cooperativity at multiple regulatory elements.
    Additional Material: 2 Ill.
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  • 8
    ISSN: 0730-2312
    Keywords: adipogenesis ; quiescence ; transcription ; mRNA ; nuclear factors ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The aim of this study was to address whether there is a fundamental difference in regulation of histone gene expression in cells that have become quiescent but retain the ability to proliferate, compared with those cells that have differentiated. We compared multiple levels of regulation of histone gene expression during 3T3-L1 pre-adipocyte differentiation. Confluent cells induced to differentiate by treatment with insulin, dexamethasone, and isobutylemethylxanthine initially exhibited an increased proliferative response compared with cells given serum alone. This initial differentiation response was associated with a twofold increase in both histone gene transcription and cellular histone mRNA levels, as well as with enhanced sequence-specific binding of nuclear factors to the proximal cell-cycle-regulatory element of the H4 histone promoter. Transforming growth factor β1, an inhibitor of 3T3-L1 differentiation, increased both the percentage of proliferating cells and the cellular levels of histone mRNA when given in addition to serum stimulation, but no enhancement of these parameters was observed upon addition of TGFβ1 to the differentiation treatment. Interestingly, although TGFβ1 enhanced binding of nuclear factors to the proximal cell cycle regulatory element of the histone promoter, these protein/DNA interactions were not associated with an increase in histone transcription. Our results are consistent with the down-regulation of histone gene expression at confluency being controlled primarily at the post-transcriptional level, in contrast to an increased involvement of transcriptional down-regulation at the onset of differentiation. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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  • 9
    ISSN: 0730-2312
    Keywords: cell cycle control ; histone gene expression ; S-phase ; regulatory signals ; differentiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Histone gene expression is restricted to the S-phase of the cell cycle. Control is at multiple levels and is mediated by the integration of regulatory signals in response to cell cycle progression and the onset of differentiation. The H4 gene promoter is organized into a series of independent and overlapping regulatory elements which exhibit selective, phosphorylation-dependent interactions with multiple transactivation factors. The three-dimensional organization of the promoter and, in particular, its chromatin structure, nucleosome organization, and interactions with the nuclear matrix may contribute to interrelationships of activities at multiple promoter elements. Molecular mechanisms are discussed that may participate in the coordinate expression of S-phase-specific core and H1 histone genes, together with other genes functionally coupled with DNA replication.
    Additional Material: 7 Ill.
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  • 10
    ISSN: 0730-2312
    Keywords: gene expression ; transcription ; histone gene ; cell cycle ; development ; DNA/protein interaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Protein/DNA interactions of the H3-ST519 histone gene promoter were analyzed in vitro. Using several assays for sequence specificity, we established binding sites for ATF/AP1-, CCAAT-, and HiNF-D related DNA binding proteins. These binding sites correlate with two genomic protein/DNA interaction domains previously established for this gene. We show that each of these protein/DNA interactions has a counterpart in other histone genes: H3-ST519 and H4-F0108 histone genes interact with ATF- and HiNF-D related binding activities, whereas H3-ST519 and H1-FNC16 histone genes interact with the same CCAAT-box binding activity. These factors may function in regulatory coupling of the expression of different histone gene classes. We discuss these results within the context of established and putative protein/DNA interaction sites in mammalian histone genes. This model suggests that heterogeneous permutations of protein/DNA interaction elements, which involve both general and cell cycle regulated DNA binding proteins, may govern the cellular competency to express and coordinately control multiple distinct histone genes.
    Additional Material: 7 Ill.
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