Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.22.1 (DNase II)
 429 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The endonuclease DNase II preferentially attacks a limited and tissue-specific portion of chromosomal DNA. This material may be separated from the bulk of chromatin DNA by virtue of its solubility in 2 mM MgCl2. The Mg2+ soluble fraction forms a specific subset of DNA sequences and is enriched four to sevenfold in sequences coding for cytoplasmic poly(A)-containing RNA and globin messenger RNA (in globin-producing cells). The bulk (70--90%) of rapidly labelled RNA is found associated with the Mg2+-soluble fraction. Transcriptionally active, Mc2+-soluble chromatin is organized into repeating subunits of DNA (200 +/- 5 base pairs) and histone. Mc2+-soluble active subunits differ from the subunits or nucleosomes of non-transcribed regions in many respects: namely, chemical composition (non-histone protein and RNA), sedimentation properties, differential sensitivity to DNase I and the single-strand-specific nuclease S1, and optical melting behaviour. These results suggest that chromatin subunits adopt a new configuration during the process of transcription.
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PMID:Organization of transcribed regions of chromatin. 2 80

Bleomycin (BLM) exclusively affects thymidine-containing compounds such as DNA and polydeoxyribonucleotides by releasing free thymine and leaving aldehyde functions. Molecular morphology and base sequence of the DNA strongly influence BLM activity. High BLM concentrations, besides modifying DNA into oligothyminic or athyminic nucleic acids, cause strand scissions. Enzymatic DNA and RNA synthesis is strongly influenced by BLM. The inhibition in DNA-dependent DNA polymerase and DNA-dependent RNA polymerase assays is of the non-competitive type. Protein biosynthesis in in vitro systems is not affected by BLM even at high concentrations. BLM turns out to be a strong inhibitor of DNase I and of DNase II; the inhibition is of the competitive type. The enzymatic activities of nucleases using RNA as substrate (RNase A, RNase B, Rnase T1, venom phosphodiesterase I and spleen phosphodiesterase II) are not influenced by this antibiotic. The antibiotic reduces cell proliferation (L5178y mouse lymphoma cells) in vitro in low concentrations by cytostasis and at higher concentrations by cytotoxicity. In BLM-treated L5178y cells, DNA synthesis is strongly reduced, while RNA and protein synthesis are not affected. In vivo, using growing quail oviducts, cell proliferation and cytodifferentiation are markedly inhibited after BLM treatment. This is attributed to the observed inhibition of DNA synthesis. RNA and protein synthesis as well as gene expression are not influenced by BLM under the conditions used. The selective inhibition of DNA synthesis in vivo may be caused by the following mechanisms: (1) competition of BLM with RNA; (2) blocking of the accessibility of DNA in chromatin to BLM, and (3) dependence from the repair processes. BLM inhibits growth of sarcomas, induced by oncogenic RNA viruses in vivo; well-developed tumours show regression after BLM treatment. Transformation of chick embryo fibroblasts by oncogenic RNA viruses in vitro and growth of these viruses is blocked by BLM; the most sensitive period for BLM inhibition is the time during the first period (integration of viral genome into cellular genome?) after infection.
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PMID:Effect of bleomycin on DNA, RNA, protein, chromatin and on cell transformation by oncogenic RNA viruses. 6 69

5-Iodo-5'-amino-2',5'-dideoxyuridine (AIdUrd) is a novel thymidine analog which inhibits herpes simplex virus, type 1 (HS-1 virus) replication in the absence of detectable host toxicity. When murine, simian, or human cells in culture are treated with [125I]AIdUrd for up to 24 hours essentially none of the nucleoside becomes cell-associated. In contrast, upon HS-1 virus infection significant radiolabel is detected in both nucleotide pools and in DNA. The major acid-soluble metabolite has been shown by enzymic and chromatographic analysis to be the 5'-triphosphate of AIdUrd. DNA from HS-1 virus-infected Vero cells labeled with [14C]thymidine, 5-[125I]iodo-2'-deoxyuridine (IdUrd), or [125I]AIdUrd was isolated by buoyant density centrifugation and subjected to digestion by pancreatic DNase I, spleen DNase II, micrococcal nuclease, spleen, and venom phosphodiesterases. Analysis of the digestion products clearly indicate that AIdUrd is incorporated internally into the DNA structure. DNA containing AIdUrd therefore contains phosphoramidate (P-N) bonds, known to be extremely acid-labile. The selective HS-1 virus-induced phosphorylation of AIdUrd and its subsequent incorporation into DNA may account for the unique biological activity of the AIdUrd nucleoside.
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PMID:Specific herpes simplex virus-induced incorporation of 5-iodo-5'-amino-2',5'-dideoxyuridine into deoxyribonucleic acid. 18 81

Hen oviduct chromatin was digested with DNase II and separated into two fractions. The MgCl2 insoluble chromatin fraction (43% of the total DNA) was enriched in nucleosome-like particles, which sedimented at 11 S and contained 185 base pairs of DNA. The MgCl2 soluble chromatin fraction (5% of the total DNA) was characterized by 5 S and 14 S peaks in sucrose gradients; Estrogen receptors in the chromatin fractions were labelled with [3H] estradiol using the steroid exchange assay. The concentration of receptors in the MgCl2 soluble chromatin was 4;5 times higher than that in the MgCl2 insoluble chromatinmin sucrose gradient analysis the 11 S particles displayed a negligible specific radioactivity suggesting that estrogen receptors mainly bind to extranucleosomal chromatin.
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PMID:Distribution of estrogen receptors in subfractions of hen oviduct chromatin. 18 84

The action of micrococcal nuclease, DNase I and DNase II on mouse TLT hepatoma chromatin revealing the periodicity of its structure as visualized by denaturing and non-denaturing gel electrophoresis, was consistent with the action of these enzymes on other chromatins. Micrococcal nuclease showed a complex subnucleosome fragment pattern based on multiples of 10 base pairs with a prominant couplet at 140/160 base pairs and the absence of the 80 base pair fragment. This couplet of the core and minimal nucleosome fragments was conspicuously present in the mononucleosomes found in the 11S fractions of a glycerol gradient centrifugation. DNase I and II produced a fairly even distribution of a 10 base pair increasing series of fragments to about 180 base pairs, a pattern also repeated in the DNA of nucleosome glycerol-gradient fractions. In limited digestions by these nucleases multinucleosomic DNA fragments are pronounced. These fragment lengths are multiples of an estimated average repeat length of nucleosome DNA of 180 base pairs. The action of the endogenous Mg/Ca-stimulated endonuclease produced only limited cuts in the hepatoma chromatin resulting primarily in multi-nucleosomic DNA fragment lengths and only upon lengthy digestion limited subnucleosomic, 10-base-pair multiple fragments are produced. The putative euchromatin-enriched fractions (50-75S) of the glycerol gradient centrifugation of autodigested chromatin, similarly, contained primarily the multinucleosomic DNA fragment lengths. These results are consistent with our previous electron microscopic demonstration that autodigested chromatin as well as the putative euchromatin-enriched fractions were composed of multi-nucleosomic chromatin segments containing a full complement of histones.
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PMID:Periodicity and fragment size of DNA from mouse TLT hepatoma chromatin and chromatin fractions using endogenous and exogenous nucleases. 20 20

To provide information on the role of nucleases in oncogenic virus infection, the activities of 3'-nucleotide phosphodiesterase (3'-NPDase), 5'-nucleotide phosphodiesterase (5'-NPDase), acid deoxyribonuclease (DNase II), and 3',5'-cyclic AMP phosphodiesterase (cAMPDase) in spleen extracts of murine sarcoma virus-infected C57BL/6 inbred mice were studied. At the peak of tumor growth and of the cell-mediated cytotoxic response (CMC) against tumor-associated antigens, 3'-NPDase, 5'-NPDase, and DNase II all showed depressed activities in the spleen, whereas the activity of cAMPDase in the spleen increased at the peak of CMC and remained elevated thereafter. Serum enzyme activities of the infected mice were also determined, and only 3'-NPD-ase in serum correlated well with CMC. Inasmuch as the correlation of the tumor growth with CMC was established in this system, further study on tumors with variance between CMC and growth is necessary to determine if serum 3'-NPDase is a useful biochemical marker for CMC in vivo.
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PMID:Nucleases and adenosine 3',5'-cyclic monophosphate phosphodiesterase activities in murine sarcoma virus (Moloney)-infected mice. 21 66

The four histones H2A, H2B, H3 and H4 from calf thymus, CHO and sea urchin gastrula cells were associated by stepwise dialysis from 2 M NaCl with SV40 DNA Form I. The in vitro-assembled chromatins were visualized by electron microscopy and the size of the DNA fragments generated by digestion with DNase II was determined. Irrespective of the origin of the histones, the size of the smallest DNA band generated at early times of digestion was about 190 base pairs, whereas oligomeric DNA bands were multiples of 140 bp. These results support our previous proposal that the four histones H2A, H2B, H3 and H4 are able to organize more than 140 bp of DNA, but do not provide any evidence that the variability of histones H2A and H2B plays a role in the variability of the DNA repeat length of native chromatins.
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PMID:The same amount of DNA is organized in in vitro-assembled nucleosomes irrespective of the origin of the histones. 21 59

Nuclei and chromatin from trout testis cells were digested with three different nucleases (DNase I, DNase II, and micrococcal nuclease), and the acid-soluble proteins that were solubilized and those remaining bound to the nuclease-resistant DNA were compared electrophoretically. With the conditions described by H. Weintraub and M Groudine [(1976) science, 193, 848-856], which we previously found to be selective in digesting actively transcribed regions in trout testis chromatin, a single chromosomal protein, H6, was solubilized. The nucleosomal histones and H1 remained insoluble, bound to the resistant DNA. In contrast, digestion with micrococcal nuclease led to a preferential solubilization of a second protein, HMG-T, together with the release of some nucleosomal histones and H1 into the soluble fraction. DNase II also discriminated between "active" and "inactive" chromatins; when a DNase II-solubilized "active" chromatin fraction was prepared, it too was enriched in H6 and HMG-T. Thus, both H6 and HMG-T, the two major low-salt extractable chromosomal nonhistone the two major low-salt extractable chromosomal nonhistone proteins from trout testis, are associated with chromatin regions selectively sensitive to nucleases. The preferential solubilization of HMG-T by micrococcal nuclease action suggests that it might be located at the internucleosomal "spacer" region.
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PMID:Selective association of the trout-specific H6 protein with chromatin regions susceptible to DNase I and DNase II: possible location of HMG-T in the spacer region between core nucleosomes. 26 31

Chromatin from trout testis at an early stage of development was digested with DNase II (deoxyribonucleate 3'-oligonucleotidohydrolase; EC 3.1.4.6), and the solubilized products were fractionated into Mg2+-soluble and -insoluble components. An examination of the histones from these fractions by one- and two-dimensional polyacrylamide gels showed that the highly acetylated species of histone H4 (di-, tri-, and tetra-acetylated) were associated mainly with the Mg2+-soluble material. Digestion of this chromatin fraction with pancreatic ribonuclease converted more than half of it to an insoluble state, and the acetylated H4 remained associated with the precipitated fraction. No changes in the other histones were noted, but two other basic proteins were also found to be associated with the Mg2+-soluble fraction. Since this fraction is enriched in transcribing gene sequences, it is concluded that the histone H4 of active genes is present in a highly acetylated state.
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PMID:Acetylated histone H4 is preferentially associated with template-active chromatin. 27 72

Human pancreatic DNase I was purified extensively from duodenal juice of healthy subjects by a procedure including ammonium sulfate fractionation, ethanol fractionation, phosphocellulose fractionation, isoelectric focusing, and gel filtration. The final preparation was free of DNase II, pancreatic RNase, alkaline phosphatase, and protease. The enzyme had a molecular weight of approximately 30,000, as determined by gel filtration on Sephadex G-100, and showed maximum activity at pH 7.2-7.6. It required divalent cations for activity, and caused single-strand breaks by endonucleolytic attack on double- as well as single-stranded DNA molecules. The enzyme was inhibited by actin and bovine pancreatic DNase I antibody.
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PMID:Purification and properties of human pancreatic deoxyribonuclease I. 41 31


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