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)

Autoimmune serum from a patient with scleroderma was shown by indirect immunofluorescence to label nucleoli in a variety of cells tested including: rat kangaroo PtK2, Xenopus A6, 3T3, HeLa, and human peripheral blood lymphocytes. Immunoblot analysis of nucleolar proteins with the scleroderma antibody resulted in the labeling of a single protein band of 34 kD molecular weight with a pI of 8.5. Electron microscopic immunocytochemistry demonstrated that the protein recognized by the scleroderma antiserum was localized exclusively in the fibrillar region of the nucleolus which included both dense fibrillar and fibrillar center regions. Therefore, we have named this protein "fibrillarin". Fibrillarin was found on putative chromosomal nucleolar organizer regions (NORs) in metaphase and anaphase, and during telophase fibrillarin was found to be an early marker for the site of formation of the newly forming nucleolus. Double label indirect immunofluorescence and immunoelectron microscopy on normal, actinomycin D-segregated, and DRB-treated nucleoli showed that fibrillarin and nucleolar protein B23 were predominantly localized to the fibrillar and granular regions of the nucleolus, respectively. RNase A and DNase I digestion of cells in situ demonstrated that fibrillarin was partially removed by RNase and completely removed by DNase. These results suggest that fibrillarin is a widely occurring basic nonhistone nucleolar protein whose location and nuclease sensitivity may indicate some structural and/or functional role in the rDNA-containing dense fibrillar and fibrillar center regions of the nucleolus.
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PMID:Fibrillarin: a new protein of the nucleolus identified by autoimmune sera. 293 2

Rhizobium phage RL38JI DNA is resistant to cleavage by a variety of restriction endonucleases, and is only partially sensitive to digestion by pancreatic DNase I or by micrococcal nuclease. We have found that a mixture of DNase I, P1 nuclease, and bacterial alkaline phosphatase will quantitatively digest RL38JI DNA to deoxyribonucleosides. HPLC analysis revealed that dCyd is nearly totally absent among these digestion products, while dGuo, dAdo, and Thd are readily detected. Three additional peaks are always present; their retention properties correspond to no known modified deoxyribonucleosides. Thus it appears that dCyd is replaced in phage RL38JI DNA by as many as 3 different modified residues.
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PMID:Replacement of the deoxycytidine residues in Rhizobium bacteriophage RL38JI DNA. 298 32

The internal promoter of the Xenopus laevis oocyte-type 5S RNA gene is preferentially cleaved by S1 and Bal-31 nucleases in plasmid DNA. S1 nuclease sensitivity is largely dependent on supercoiling; however, Bal-31 cleaves within the 5S RNA gene in linear as well as in supercoiled DNA. The S1 nuclease-hypersensitive site is centered at position +48-52 of the gene at the 5' boundary of the promoter. A DNAase I-hypersensitive site is induced at this position upon binding of the transcription factor, TFIIIA, specific for the 5S RNA gene. The somatic-type 5S RNA gene promoter is not preferentially cleaved by S1 nuclease or Bal-31 nuclease in supercoiled DNA, nor does TFIIIA induce a DNase I site at position +50. This differential promoter response may be related to a 4-fold difference in TFIIIA affinity between the oocyte and somatic 5S RNA genes.
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PMID:Torsional stress induces an S1 nuclease-hypersensitive site within the promoter of the Xenopus laevis oocyte-type 5S RNA gene. 298 60

In several lines of Rous sarcoma virus (RSV)-transformed rat cells the proviruses are in a configuration typical of active eukaryotic genes. They are sensitive to pancreatic DNase I, with sites hypersensitive to nuclease near the 5' end of the genome, they are close to the nuclear 'cage' and they show a low level of cytosine methylation in CpG doublets. In contrast, in phenotypically untransformed hybrids between these cells and uninfected rat or mouse cells, RSV inactivity is associated with hypermethylation of the provirus, reduced DNase I sensitivity (in two out of three examples) and, where examined, relative remoteness from the nuclear cage. These changes in proviral configuration, which occur rarely in spontaneous reversion of transformed cells, can thus be induced at high frequency and stability in cell hybrids by trans-acting influences of the uninfected parents.
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PMID:The chromatin structure of Rous sarcoma proviruses is changed by factors that act in trans in cell hybrids. 299 Aug 99

In several bursal lymphoma cell lines in which c-myc transcription is regulated by avian leukosis virus (ALV) long terminal repeat (LTR) sequences, protein synthesis inhibition decreases the transcriptional activity of c-myc as well as other LTR driven viral genes. This decrease in transcription is associated with a change in the chromatin structure of c-myc, as measured by deoxyribonuclease I (DNase I) hypersensitivity, and a shift of transcription from the LTR to the normal c-myc promoter. In contrast, cycloheximide had little or no effect on the transcription of LTR driven genes in infected chicken embryo fibroblasts treated with the drug. These results suggest that a labile, cell type-specific protein may interact with the retroviral LTR and regulate transcription of genes under LTR control. Further, the results demonstrate that the increase in intracellular concentration of c-myc RNA induced by cycloheximide treatment of normal cells is the result of stabilization of this message.
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PMID:Enhanced transcription of c-myc in bursal lymphoma cells requires continuous protein synthesis. 299 73

recA protein, in the presence of ATP, polymerizes on single-stranded DNA (plus strand) to form a presynaptic nucleoprotein filament that pairs with linear duplex DNA and actively displaces the plus strand from the recipient molecule in a polarized fashion to form a new heteroduplex molecule. The interaction between recA protein and DNA during strand exchange was studied by labeling different strands and probing the intermediate with pancreatic deoxyribonuclease I (DNase I) or restriction endonuclease. The incoming single strand was resistant to DNase I in the original nucleoprotein filament and remained resistant even after extensive strand exchange had occurred. Both strands of the parental duplex molecule were sensitive to DNase I in the absence of joint molecule formation; but as strand exchange progressed following homologous pairing, increasing stretches of the parental plus strand became resistant, whereas the complementary parental minus strand remained sensitive to DNase I throughout the reaction. Except for a region of 50-100 base pairs at the end of the newly formed heteroduplex DNA where strand exchange was initiated, the rest of the heteroduplex region was resistant to cleavage by restriction endonucleases. The data suggest that recA protein promotes strand exchange by binding both the incoming and outgoing strands of the same polarity, whereas the complementary strand, which must switch pairing partners, is unhindered by direct contact with the protein.
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PMID:Patterns of nuclease protection during strand exchange. recA protein forms heteroduplex DNA by binding to strands of the same polarity. 300 81

A sensitive gel retention assay has been utilized to detect proteins from uninfected Hela nuclei which interact with the adenovirus type 2 enhancer. This assay has been employed to monitor fractionation of nuclear extracts. Three enhancer binding factors were resolved by chromatography on DEAE-Sepharose and one of the factors was further purified by chromatography on heparin-Sepharose. DNase protection experiments have shown that the heparin-Sepharose fraction contains a factor which binds predominantly to the conserved sequence GTGGAAATTT present at position 160 in the adenovirus type 2 genome and found in many viral and cellular enhancers. Protection of this sequence from DNase I digestion was abolished by competition with a synthetic duplex oligonucleotide spanning bases 144-181. This region corresponds to the sequence defined by Hen et al. as possessing enhancer function. Competition experiments indicated that the enhancer binding factor also bound, albeit with reduced affinity, to multiple sites in the Ela upstream region located between positions 192 and 353. Within the sequences which compete are regions with homology to the high affinity site at position 160. The enhancer binding factor also binds with high affinity to sequences within the SV40 enhancer demonstrating that this factor interacts with sequences common to both the adenovirus and SV40 enhancers.
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PMID:A cellular protein binds to a conserved sequence in the adenovirus type 2 enhancer. 303 10

Extensive digestion of Chinese hamster metaphase chromosomes with Alu I, Hae III and Hinf I released up to 40 distinct chromosomal proteins. Some of the proteins released by Hae III or Hinf I were enriched in the protein moiety liberated by Alu I but several proteins released by Hae III were not released by Alu I digestion. The amount of chromosomal protein released by deoxyribonuclease I (DNase I) was comparable to that liberated by the three restriction enzymes so far tested, while only four abundant protein species were detectable in the protein moiety released by DNase I. Two of them with molecular weights of 58,000 and 50,000 were also released by the three restriction enzymes and are similar in size to those found previously in the core-like structure of histone-depleted chromosomes.
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PMID:A comparative study on proteins released from metaphase chromosomes after digestion with restriction endonucleases and deoxyribonuclease I. 303 76

We have investigated the effects of intermolecular disulfide crosslinking and temperature-dependent insolubilization of nuclear proteins in vitro on the association of the polyoma large T antigen with the nuclear matrix in polyomavirus-infected mouse 3T6 cells. Nuclear matrices, prepared from polyomavirus-infected 3T6 cells by sequential extraction of isolated nuclei with 1% Triton X-100 (Triton wash), DNase I, and 2 M NaCl (high salt extract) at 4 degrees C, represented 18% of total nuclear protein. Incubation of nuclei with 1 mM sodium tetrathionate (NaTT) to induce disulfide crosslinks or at 37 degrees C to induce temperature-dependent insolubilization prior to extraction, transferred an additional 9-18% of the nuclear protein from the high salt extract to the nuclear matrix. This additional protein represented primarily an increased recovery of the same nuclear protein subset present in nuclear matrices prepared from untreated nuclei. Major constituents of chromatin including histones, hnRNP core proteins, and 98% of nuclear DNA were removed in the high salt extract following either incubation. Polyoma large T antigen was quantified in subcellular fractions by immunoblotting with rat anti-T ascites. Approximately 60-70% of the T antigen was retained in nuclei isolated in isotonic sucrose buffer at pH 7.2. Most (greater than 95%) of the T antigen retained in untreated nuclei was extracted by DNase-high salt treatment. Incubation at 37 degrees C or with NaTT transferred most (greater than 95%) of the T antigen to the nuclear matrix. T antigen solubilized from NaTT-treated matrices with 1% SDS sedimented on sucrose gradients as a large (50-S) complex. These complexes, isolated by immunoprecipitation with anti-T sera, were dissociated by reduction with 2-mercaptoethanol, and SDS-PAGE analysis revealed that T antigen was crosslinked in stoichiometric amounts to several host proteins: 150, 129, 72, and 70 kDa. These host proteins were not present in anti-T immunoprecipitates of solubilized nuclear matrices prepared from iodoacetamide-treated cells. Our results suggest that the majority of polyomavirus large T antigen in infected cells is localized to a specific subnuclear domain which is distinct from the bulk chromatin and is closely associated with the nuclear matrix.
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PMID:Protein disulfide crosslinking stabilizes a polyoma large T antigen-host protein complex on the nuclear matrix. 304 Apr 47

Myogenesis proceeds stepwise from pluripotential stem cell to differentiated myotube. The precise number of transitions that occur along the developmental pathway remains to be determined. We examined the myogenic pathway as modelled by mouse mesodermal stem cell and muscle cell lines for stage-specific alterations in the chromatin structure of the acetylcholine receptor delta and gamma subunit genes. We reasoned that such an analysis would allow us to observe either the primary events in the activation of these muscle-specific genes or processes secondary to the binding of muscle-specific regulatory proteins. We probed chromatin structure with DNase I (deoxyribonuclease I) and precisely mapped to the 5' ends of the delta and gamma genes DNase I hypersensitive (DH) sites whose induction is unique to each myogenic stage. Putative mesodermal stem cells have the simplest pattern of DH sites with no sites near the 5' ends of the delta and gamma genes, whereas differentiated myotubes express the most complex pattern; the myoblast pattern is intermediate and of two types. In muscle cell lines where differentiation must be induced the myoblasts have a simple pattern (one more site than stem cells); in muscle lines where differentiation is spontaneous the myoblasts express a complex pattern of DH sites (one less site than myotubes). Inducible myoblasts seem to be arrested in an earlier step in the myogenic pathway than spontaneously differentiating myoblasts. Thus, myogenic activation of acetylcholine receptor subunit genes appears to be a stepwise process that can be detected by chromatin structural changes specific to four distinct stages of muscle development: stem cell, early myoblast, late myoblast, and differentiated myotube.
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PMID:Studies of acetylcholine receptor subunit gene expression: chromatin structural changes during myogenesis. 305 34


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