Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.21.1 (DNase)
7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We identified the factor(s) that bind to the chicken erythroid-cell-specific histone H5 enhancer region which is located on the 3' end of the gene. In DNAase I footprinting and u.v. cross-linking experiments with nuclear extracts from adult chicken immature erythrocytes, we determined that the trans-acting factor GATA-1 was the predominating protein interacting with the histone H5 enhancer. GATA-2 and GATA-3 were not detected. In contrast, gel-mobility-shift assays and competition experiments demonstrated that several specific complexes formed with the histone H5 enhancer region. Gel-mobility-shift assays with 23 bp oligonucleotides containing the GATA-binding site (AGATAA) of the histone H5 enhancer or of the beta-globin enhancer showed that the GATA sequence was sufficient for the formation of at least five complexes. Diagonal mobility-shift assays demonstrated that multisubunit complexes were forming with the GATA-1 protein. Our interpretation of the results is that GATA-1 interacts with a protein of approx. 105 kDa which, in turn, can associate with protein or protein complexes of approx. 26 kDa, 146 kDa and a protein(s) of molecular mass greater than 450 kDa. The different multisubunit complexes formed via the trans-acting factor GATA-1 may impart different transcriptional responses to the promoter and enhancer elements of the histone H5 and globin genes.
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PMID:Multisubunit erythroid complexes binding to the enhancer element of the chicken histone H5 gene. 159 Jul 78

We have analysed the chromatin features of DNA regions encompassing human epsilon, G gamma, A gamma, delta and beta globin structural genes in fetal and adult erythroid cells on the one hand and adult lymphocytes on the other. Highly purified nuclei from these cells were submitted to DNase I digestion and the kinetic data were obtained from the percentage of residual hybridization of defined regions in Southern blots. Our results, as others have shown by different approaches, indicate that the structural genes of the beta-globin cluster are generally more sensitive to DNase I in the erythroid cells than in non-erythroid cells. Thus a domain of DNase I sensitivity related to the committed state is defined. In addition we show that within this DNase-I-sensitive beta cluster domain, individual genes of the cluster are arranged in subdomains of differential DNase I sensitivity, which correlate with their expression status. Furthermore the differential expression of the two fetal genes in the fetal stage is shown to be directly proportional to the degree of hypomethylation of these genes.
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PMID:Differences in DNase I sensitivity and methylation within the human beta-globin gene domain and correlation with expression. 242 May 88

We have localized a set of T cell-specific DNAase I hypersensitive sites in the 3'-flanking region of the human CD2 gene. A 5.5 kb BamHI-XbaI fragment containing these DNAase I hypersensitive sites conferred efficient, copy number-dependent, T cell-specific expression of a linked human CD2 minigene, independent of the position of integration in the transgenic mouse genome. When linked to the mouse Thy-1.1 gene or the human beta-globin gene, this fragment conferred the same T cell-specific expression, independent of its orientation. These results suggest that this flanking region is both necessary and sufficient for full tissue-specific activation of homologous and heterologous genes in transgenic mice.
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PMID:Human CD2 3'-flanking sequences confer high-level, T cell-specific, position-independent gene expression in transgenic mice. 256 17

The beta-globin and histone H5 genes are transcriptionally active in immature chicken erythrocytes and potentially active in mature erythrocytes. In both immature and mature erythrocytes, the majority of these erythroid-specific gene sequences are located in two chromatin fractions: the low-salt-insoluble residual nuclear material and the 0.15 M-NaCl-soluble oligo- and poly-nucleosomes. These salt-soluble chromatin fragments are enriched in hyperacetylated species of H4 and H2B, ubiquitinated and polyubiquitinated species of H2A and H2B and are depleted of linker histones H1 and H5. The competent, transcriptionally inactive embryonic epsilon-globin gene, which is part of the DNAase I-sensitive beta-globin domain, is highly enriched in the 0.15 M-NaCl-soluble polynucleosome fraction but not in the insoluble nuclear material. The repressed vitellogenin gene shows no enrichment in either of these fractions. These results suggest that only those genes that are expressed or have the potential for expression are enriched in the low-salt-insoluble nuclear material of immature or mature erythrocytes. The enrichment of active genes in the low-salt-insoluble residual nuclear material of immature erythrocytes is not dependent on on-going transcription, the presence of RNA or changes in the amount of acetylated histone species. Our results are consistent with the hypothesis that active and potentially active genes are insoluble because of the presence of preinitiation transcription complexes.
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PMID:Chromatin structure of erythroid-specific genes of immature and mature chicken erythrocytes. 260 93

Human alpha- and beta-globin genes were separately fused downstream of two erythroid-specific deoxyribonuclease (DNase) I super-hypersensitive sites that are normally located 50 kilobases upstream of the human beta-globin gene. These two constructs were coinjected into fertilized mouse eggs, and expression was analyzed in transgenic animals that developed. Mice that had intact copies of the transgenes expressed high levels of correctly initiated human alpha- and beta-globin messenger RNA specifically in erythroid tissue. An authentic human hemoglobin was formed in adult erythrocytes that when purified had an oxygen equilibrium curve identical to the curve of native human hemoglobin A (Hb A). Thus, functional human hemoglobin can be synthesized in transgenic mice. This provides a foundation for production of mouse models of human hemoglobinopathies such as sickle cell disease.
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PMID:Synthesis of functional human hemoglobin in transgenic mice. 277 49

We have used the gel retardation and DNAase I assays to investigate the binding of nuclear proteins to the human beta-globin promoter. Upon incubation with beta-globin promoter fragments containing the duplicated CACCC boxes, nuclear proteins from human erythroid cells generate complexes yielding four retarded bands in acrylamide gels; the three slowest bands are common to both erythroid and non erythroid cells. The fast band is present only in K562 erythroleukemic cells induced to differentiation and hemoglobin accumulation and in fetal and adult erythroblasts, but absent in uninduced K562 cells. Binding occurs on a short DNA region including the proximal CACCC box, and is not significantly competed by excess gamma-globin fragments containing the CACCC box; the CACCC box appears to be essential for this binding, as shown by the failure of a fragment containing a natural beta-thalassemic mutation (-87, C----G) to bind significantly to nuclear factors. These data suggest that the erythroid specific CACCC binding factor might play a role in the developmental activation of beta-globin transcription.
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PMID:An erythroid specific nuclear factor binding to the proximal CACCC box of the beta-globin gene promoter. 283 28

We have studied the properties of a factor or factors that bind selectively to the 5' flanking region of the chicken adult beta-globin (beta A-globin) gene. We previously showed that these components, when bound with histones on plasmids containing the region, confer on the complex a pattern of hypersensitivity to nuclease digestion similar to that in the nucleus. We have now measured the abundance of the factor(s) in partially purified preparations, and the affinity constants for binding to specific and nonspecific DNA sequences. Footprinting studies of the specific complex with DNAase I and II reveal two discrete protected regions within the hypersensitive domain. When these regions are physically separated, they interact with the factor(s) independently, suggesting that each region binds one or more distinct components. The footprint patterns of our complexes in vitro agree with the patterns observed in intact chicken erythrocyte nuclei. These complexes thus are on the transcriptionally active beta A-globin gene in vivo.
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PMID:Interaction of specific nuclear factors with the nuclease-hypersensitive region of the chicken adult beta-globin gene: nature of the binding domain. 298 43

Messenger RNAs in eukaryotic cells exhibit a broad range of stabilities in vivo. Globin mRNA has a half life in excess of 50 h, but the half life of the c-myc oncogene mRNA is less than 20 min. Regulation of gene expression may be accomplished by a variety of mechanisms, including altering mRNA stability. We have examined the nuclear and cytoplasmic fractions of cells for factors affecting the metabolism of mRNA. Here we report that a HeLa whole-cell extract contains a factor that protects beta-globin mRNA from attack by RNases in a mouse erythroleukemia cell cytoplasmic extract. The factor is non-dialysable, inactivated by proteinase K and heat treatment, and resistant to RNase and DNase digestion. The HeLa cell factor resembles placental RNase inhibitor in that the mRNA-protecting activity is effective against RNase A and that treatment of the extract with N-ethylmaleimide completely destroys the protective activity. However, purified placental RNase inhibitor was unable to inhibit the RNase activity in the MELC cytoplasmic extract. These results suggest that the HeLa cell extract contains an RNase inhibitor (or inhibitors) with an activity or specificity that is distinct from that of placental RNase inhibitor.
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PMID:Cellular factor affecting the stability of beta-globin mRNA. 316 61

The nucleotide sequence of the 5' end distal region of the human c-K-ras gene promoter was determined. This region, coincident with a variable DNAse I hypersensitive site in native chromatin, contains sequence similarities with known enhancers. A 400 bp MstII DNA fragment of this region stimulated in cis the correctly initiated transcription of the human beta-globin gene in transfected Hela cells. The stimulation of beta-globin transcription (5-6 fold) was dependent on the distance and orientation of the c-K-ras sequences and on the presence of the CCAAT and CACCC elements in the beta-globin promoter. Interaction of nuclear factors with these c-K-ras sequences was analysed by DNAase I footprinting assays using Hela nuclear extracts. A protein binding to these sequences was identified as nuclear factor 1 (NF-1) by DNAase I competition footprinting experiments. However, disruption of the c-K-ras NF-1 binding site by insertion mutagenesis had no effect on the transcriptional activity of the c-K-ras element.
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PMID:Initial characterization of a potential transcriptional enhancer for the human c-K-ras gene. 328 54

The chromatin of several genes was assayed for sensitivity to DNAase I and for solubility as polynucleosomes in 0.15 M NaCl. The degree of solubility of chromatin fragments as polynucleosomes in 0.15 M NaCl correlates well with the sensitivity to DNAase I for several genes. Chromatin of repressed, housekeeping and erythroid-specific genes can be distinguished as distinct groups by the degree to which they display these properties. NaCl precipitation of chromatin fragments stripped and then reconstituted with varying quantities of H1 and H5 (linker) histones indicate that the polynucleosomes of erythroid-specific genes have altered interaction with these histones. Linker histones interacted with bulk chromatin and in the chromatin of the repressed ovalbumin and vitellogenin genes to form salt precipitable structures. Chromatin of erythroid-specific genes (histone H5 and beta-globin) as well as that of the histone H2A.F gene was resistant to linker histone induced precipitation.
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PMID:Erythroid-specific gene chromatin has an altered association with linker histones. 339 83


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