Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:BIOD00001 (DNase I)
 8,324 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Deoxyribonucleic acid polymerase-beta (EC 2.7.7.7) FROM THE Novikoff hepatoma has been purified over 200 000-fold (based on the increase in specific activity), by ammonium sulfate fractionation and chromatography on DEAE-Sephadex, phosphocellulose, hydroxylapatite, and DNA-cellulose. The enzyme is remarkably stable through all stages of purification until DNA-cellulose chromatography when it must be kept in buffers containing 0.5 M NaCl and 1 mg/ml bovine serum albumin for stability. The enzyme appears to be homogeneous as evidenced by a single stainable band when subjected to electrophoresis in polyacrylamide gels of different porosity. The stainable band corresponds to the DNA polymerase as determined by slicing sister gels and assaying for enzyme activity. The specific activity of the homogeneous preparation is about 60 000 units/mg. The enzyme lacks detectable exonuclease or endonuclease activity. It has a molecular weight of 32 000 as determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis. In sucrose gradients, the molecular weight is estimated at 31 000. The isoelectric point of the hydroxylapatite fraction enzyme is 8.5. The Novikoff beta-polymerase requires all four deoxyribonucleoside triphosphates, primer-template, and a divalent cation for maximal activity. The apparent Km for total deoxyribonucleoside triphosphate is 7-8 muM and for DNA 125 mug/ml. Activated DNA, rendered 7% acid soluble by DNase I, is the preferred primer-template, although a number of synthetic polynucleotides can by efficiently utilized, particularly in the presence of Mm2+ optimum is 7 mM; the Mn2+ optimum is 1 mM. The pH optimum is 8.4 in Tris-HCl or 9.2 in glycine buffer. The beta-polymerase is sstimulated about twofold by NaCl or KCl at an optimum of 50-100 MM, and the enzyme maintains considerable activity at high ionic strengths. The DNA polymerase is inhibited by ethanol, acetone, and a variety of known polymerase inhibitors. Glycols stimulate the enzyme as does spermine or spermidine. Unlike most beta-polymerases, the Novikoff enzyme is moderately sensitive to N-ethylmaleimide.
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PMID:Novikoff hepatoma deoxyribonucleic acid polymerase. Purification and properties of a homogeneous beta polymerase. 18 3

DNA polymerase induced by bacteriophage T5 was purified and characterized using mainly circular duplex DNA of bacteriophage PM2 with single strand breaks formed by DNase I action. A purification procedure is described which has consistently yielded DNA polymerase preparations with only one detectable protein band after polyacrylamide gel electrophoresis of either native protein in Tris-glyase preparations utilized both denatured DNA and nicked DNA as primer-templates, although at 37 degrees the activity with denatured DNA was much greater. Polymerase activities with both kinds of primer-templates were shown to be associated with one phage-induced protein. DNA synthesis with nicked DNA as primer-template increased with increasing numbers of single strand breaks. Essentially all such breaks were repairable by ligase. Alkaline sucrose gradient centrifugation showed that synthesis occurred with the strand which had a single strand break as a primer yielding DNA longer than one phage DNA unit length. Newly synthesized DNA was covalently linked to the primer strand. Thus the synthesis very likely occurred by strand displacement; this is supported by electron micrographs shown in the Appendix.
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PMID:Characterization of DNA polymerase induced by bacteriophage T5 with DNA containing single strand breaks. 77 33

After high dose methotrexate (CAS 59-05-2) therapy of children with non-metastatic osteosarcoma the neutral DNase activity is missing in lymphocytes and in phytohemagglutinin (PHA)-stimulated lymphocytes. The neutral DNase activity reappeared in lymphocytes 14 days and in PHA-stimulated lymphocytes 10 days after the end of therapy. The DNA polymerase activity is low when neutral DNase is missing and increases when neutral DNase activity reappeared. The neutral DNase activity in lymphocytes and in PHA-stimulated lymphocytes is probably identical with DNase I. Drug induced changes in DNA conformation can enhance DNase I cleavage rate. It is assumed, that high dose methotrexate alters DNA conformation and therefore binds DNase I; after this, free DNase I is no more detectable.
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PMID:Missing neutral DNase activity in lymphocytes and phytohemagglutinin-stimulated lymphocytes after high dose methotrexate therapy. 141 65

We report on the discovery and isolation of DNA- and RNA-containing macromolecular nuclear complexes whose purified major DNA possessed electrophoretic mobilities of approximately 90 and approximately 25 kbp. The deoxyribonucleoprotein-ribonucleoprotein complexes contain RNA and DNA polymerase and primase activities and were isolated from nuclei of murine RAW117 large-cell lymphoma cells by restriction digestion with Msp-I, gentle extraction with solutions containing MgCl2, but without chelating agents, and low ionic strength gel electrophoresis. Two-dimensional (isoelectric focusing/M(r)) gel electrophoresis and silver staining of the proteins of the complexes after treatment with DNase I indicated the presence of approximately 30 protein components. In vitro DNA and RNA polymerase/primase assays showed that the DNP/RNP complexes had very high enzyme specific activities. Using the DNP/RNP complexes a discrete DNA polymerase alpha product of approximately 85 kbp was synthesized that was not synthesized in the presence of the DNA polymerase alpha inhibitor aphidicolin. RNA polymerase assays in the presence of excess alpha-amanitin indicated that the complexes possessed significant RNA polymerase I activity. Preparing the complexes at various times after the release of cells from a double thymidine block showed the complexes as well as the complex-associated enzyme activities to be cell-cycle dependent. The DNA and RNA polymerase-related activities were highest in late S phase, 7 and 9 h, respectively, after release from the double thymidine block. The complexes synthesized a specific in vitro DNA polymerase product using endogenous substrate and nucleotide precursors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nucleoprotein complexes released from lymphoma nuclei that contain the abl oncogene and RNA and DNA polymerase and RNA primase activities. 142 73

UvrA, UvrB, and UvrC initiate nucleotide excision repair by incising a damaged DNA strand on each side of the damaged nucleotide. This incision reaction is substoichiometric with regard to UvrB and UvrC, suggesting that both proteins remain bound following incision and do not "turn over." The addition of only helicase II to such reaction mixtures turns over UvrC; UvrB turnover requires the addition of helicase II, DNA polymerase I, and deoxynucleoside triphosphates. Column chromatography and psoralen photocross-linking experiments show that following incision, the damaged oligomer remains associated with the undamaged strand, UvrB, and UvrC in a post-incision complex. Helicase II releases the damaged oligomer and UvrC from this complex, making repair synthesis possible; DNase I footprinting experiments show that UvrB remains bound to the resulting gapped DNA until displaced by DNA polymerase I. The specific binding of UvrB to a psoralen adduct in DNA inhibits psoralen-mediated DNA-DNA cross-linking, yet promotes the formation of UrvB-psoralen-DNA cross-links. The discovery of psoralen-UvrB photocross-linking offers the potential of active-site labeling.
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PMID:Post-incision steps of nucleotide excision repair in Escherichia coli. Disassembly of the UvrBC-DNA complex by helicase II and DNA polymerase I. 153 Sep 37

Nuclear factor I (NFI) or its isolated DNA-binding domain (NFI-BD) enhances initiation of adenovirus DNA replication up to 50-fold at low concentrations of the precursor terminal protein-DNA polymerase (pTP-pol) complex. Both in solution and when bound to DNA, NFI-BD can form a complex with pTP-pol. To investigate the mechanism of enhancement by NFI, we determined the stability of a functional preinitiation complex formed in vitro between pTP-pol and the origin. Challenge experiments with a distinguishable template containing an identical origin revealed that in the absence of NFI, this preinitiation complex was very sensitive to competition for pTP-pol. Addition of NFI-BD increased the half-life of the complex at least 10-fold and led to the formation of a template-committed preinitiation complex. In agreement with this, binding of pTP-pol to origin DNA in band-shift assays was enhanced by NFI. By DNase I footprinting we show that the specificity of binding as well as induction of structural changes in origin DNA by pTP-pol are increased by NFI. These results indicate that NFI, by binding and positioning pTP-pol, stabilizes the complex between pTP-pol and the core origin, and thus enhances initiation of DNA replication.
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PMID:Nuclear factor I enhances adenovirus DNA replication by increasing the stability of a preinitiation complex. 153 46

Initiation of adenovirus DNA synthesis is preceded by the assembly of a nucleoprotein complex at the origin of DNA replication containing three viral proteins, preterminal protein, DNA polymerase and DNA binding protein, and two cellular proteins, nuclear factors I and III. While sequence specific interactions of the cellular proteins with their cognate sites in the origin of DNA replication are well characterized, the question of how the viral replication proteins recognize the origin has remained unanswered. Preterminal protein and DNA polymerase were therefore purified to homogeneity from recombinant baculovirus infected insect cells. Gel filtration demonstrated that while DNA polymerase existed in monomeric and dimeric forms, preterminal protein was predominantly monomeric and when combined the proteins formed a stable heterodimer. In a gel electrophoresis DNA binding assay each of the protein species recognized DNA within the origin of DNA replication with unique specificity. Competition analysis and DNase I protection experiments revealed that although each protein could recognize the origin, the heterodimer did so with enhanced specificity, protecting bases 8-17 from cleavage with the nuclease. Thus the highly conserved 'core' of the origin of DNA replication, present in all human adenoviruses, is recognized by the preterminal protein--DNA polymerase heterodimer.
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PMID:Recognition of the adenovirus type 2 origin of DNA replication by the virally encoded DNA polymerase and preterminal proteins. 153 47

To study the antiproliferative response of B cells to interferon-alpha (IFN-alpha) at the molecular level, we developed a cell-free system to assess DNA synthesis in nuclei isolated from IFN-sensitive Daudi B lymphoblastoid cells. [3H]dTTP incorporation in isolated nuclei was shown to be representative of replicative DNA synthesis by evidence that (i) incorporation was dependent on ATP and all four nucleoside precursors, (ii) incorporation was inhibited greater than 97% by aphidicolin, a specific inhibitor of DNA polymerase alpha and delta, and (iii) the DNase I-sensitive product banded in neutral CsCl at a density indicative of replicative DNA. This cell-free model was used in conjunction with flow cytometric cell cycle analysis to determine the effect of IFN-alpha on DNA synthesis in Daudi cells. The addition of IFN-alpha to an IFN-growth sensitive Daudi subclone in G0/early G1 inhibited the initiation of DNA synthesis, assessed in isolated nuclei, and prevented the progression of cells into S phase. IFN-alpha failed to inhibit DNA synthesis or cell cycle progression when added to IFN-sensitive Daudi cells in late G1/early S phase or to an IFN-resistant Daudi subclone. These studies suggest that IFN-alpha inhibits DNA replication and cellular proliferation in Daudi B cells by interfering with G1 cell cycle events.
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PMID:DNA synthesis in nuclei isolated from Daudi B cells: a model to study the antiproliferative mechanisms of interferon-alpha. 157 80

HeLa S3 cells were synchronized by a double thymidine block or aphidicolin treatment and the levels of nuclear matrix-bound DNA polymerase alpha activity were then measured using activated calf thymus DNA as template. The nuclear matrix was obtained by 2 M NaCl extraction and DNase I digestion of isolated nuclei incubated at 37 degrees C for 45 min prior to subfractionation. In all phases of the cell cycle 25-30% of nuclear DNA polymerase alpha activity remained matrix-bound, even when cells were in the G1 phase. No dynamic association of DNA polymerase alpha activity with the matrix was seen, at variance with previous results obtained in regenerating rat liver. The variations measured in matrix-bound activity closely followed those detected in isolated nuclei throughout the cell cycle. If nuclei were not heat-stabilized very low levels of DNA polymerase alpha activity were measured in the matrix (1-2% of total nuclear activity). Heat incubation of nuclei failed to produce any enrichment in matrix-associated newly replicated DNA, whereas the sulfhydryl cross-linking chemical sodium tetrathionate did. Therefore the results obtained after the heat stabilization procedure do not completely fit with the model that envisions the nuclear matrix as the active site where eucaryotic DNA replication takes place.
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PMID:The effect of in vitro heat exposure on the recovery of nuclear matrix-bound DNA polymerase alpha activity during the different phases of the cell cycle in synchronized HeLa S3 cells. 163 41


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