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)

The ability of different metal ions to promote transformation of Pseudomonas aeruginosa by deoxyribonucleic acid of the plasmid RP1 was examined. CaCl2, MgCl2, and MnCl2 were found to promote such transformation, although at different frequencies and with the optimum response at different concentrations. Only MgCl2 promoted transfection of P. aeruginosa by the linear deoxyribonucleic acid of phage F116. CaCl2 was demonstrated to allow adsorption and entry into the cell of F116 deoxyribonucleic acid such that it became resistant to exogenous deoxyribonuclease, but phage production occurred only when MgCl2 was provided. Inactivation of linear phage deoxyribonucleic acid taken up in the absence of MgCl2 was observed. The transfection frequencies at various concentrations of MgCl2 were compared, and the optimum response occurred at the concentration which promoted the highest frequency of transformation by RP1 deoxyribonucleic acid.
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PMID:Transformation and transfection of Pseudomonas aeruginosa: effects of metal ions. 11 40

DNA synthesis was studied in mouse ascites sarcoma cells using a permeable cell system. The sarcoma was induced by the Schmidt-Ruppin strain of Rous sarcoma virus. The cells were made permeable to nucleoside triphosphates by treatment with a hypotonic buffer containing 10 mM Tris Cl, 4 mM MgCl2, 1 mM EDTA, and 6 mM 2-mercaptoethanol (pH 8.0). DNA-synthetic activity in the permeable cells was highly dependent on four deoxyribonucleoside triphosphates, adenosine triphosphates, Mg2+, and a proper ionic environment. The activity was stimulated about 50% by the addition of an appropriate concentration of cytidine triphosphate, guanosine triphosphate, and uridine triphosphate in an assay mixture containing adenosine triphosphate and four deoxyribonucleoside triphosphates. DNA synthesis was confined to the nucleus and was sensitive to N-ethylmaleimide and DNase. The activity assayed by the permeable cell system correlated closely with the DNA-replicating activity assayed by [3H]deoxythymidine incorporation in intact cells. The close correlation between DNA synthesis in vitro and in vivo was further confirmed in cultured sarcoma cells synchronized with DNA synthesis. Analysis of the DNA synthesized in vitro by alkaline cesium sulfate density gradient centrifugation showed that over half the DNA synthesized in permeable cells was due to elongation of strands initiated in vivo. The permeable cell system appears to be a useful method for examining DNA replication of cells in suspensions.
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PMID:DNA synthesis inpermeable mouse ascites sarcoma cells. 18 30

The deoxyribonuclease induced in KB cells by herpes simplex virus (HSV) type 1 and type 2 has been purified. Both enzymes are able to completely degrade single- and double-stranded DNA yielding 5'-monophosphonucleotides as the sole products. A divalent cation, either Mg2+ or Mn2+, is an absolute requirement for catalysis and a reducing agent is necessary for enzyme stability. The maximum rate of reaction is achieved with 5 mM MgCl2 for both HSV-1 and HSV-2 DNase. The optimum concentration for Mn2+ is 0.1 to 0.2 mM and no exonuclease activity is observed when the concentration of Mn2+ is greater than 1 mM. The rate of reaction at the optimal Mg2+ concentration is 3- to 5-fold greater than that at the optimal Mn2+ concentration. In the presence of Mg2+, the enzymes are inhibited upon the addition of Mn2+, Ca2+, and Zn2+. The enzymatic reaction is also inhibited by spermine and spermidine, but not by putrescine. Crude and purified HSV-1 and HSV-2 DNase can degrade both HSV-1 and HSV-2 DNA, but native HSV-1 DNA is hydrolyzed at only 22% of the rate and HSV-2 DNA at only 32% of the rate of Escherichia coli DNA. Although HSV-1 and HSV-2 DNase were similar, minor differences were observed in most other properties such as pH optimum, inhibition by high ionic strength, activation energy, and sedimentation coefficient. However, the enzymes differ immunologically.
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PMID:The deoxyribonuclease induced after infection of KB cells by herpes simplex virus type 1 or type 2. I. Purification and characterization of the enzyme. 20 46

alpha and beta DNA polymerases (DNA nucleotidyltransferase; deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7) were isolated from nuclear and cytoplasmic fractions of rat livers exposed to a carcinogenic regimen with the hepatocarcinogen N-2-fluorenylacetamide and from 24-hr regenerating liver. The fidelity of polymerization of these enzymes was compared by determining the incorporation of noncomplementary deoxyribonucleoside triphosphates (misincorporation) on a poly(dA-dT).poly(dA-dT) template, with MnCl2 and MgCl2 as divalent cations. Our initial studies indicate that the cytoplasmic alpha polymerases from carcinogen-exposed rat livers were strikingly error-prone whereas the nuclear and cytoplasmic beta polymerases retained their fidelity throughout the feeding cycles. The misincorporation was significantly accentuated by MnCl2 compared with that obtained with MgCl2 as divalent cation. The products were sensitive to pancreatic DNase I digestion, indicating that the noncomplementary bases had been incorporated by the polymerization process. Nuclear alpha polymerase showed some degree of infidelity but less than that of cytoplasmic alpha polymerase.
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PMID:Decreased fidelity of DNA polymerase activity during N-2-fluorenylacetamide hepatocarcinogenesis. 28 2

Double-stranded deoxyribonucleic acid (DNA) from bacteriophage lambda is a good template for wheat germ DNA-dependent ribonucleic acid (RNA) polymerase II. We delineated conditions for obtaining maximum polymerase activity using as template both the relatively intact DNA extracted from the the lambda phage and DNA into which single-strand nicks have been introduced by deoxyribonuclease (DNase) I digestion. The deliberate introduction of nicks produces a modest increase in transcription. The NaCl and MgCl2 optima are broader with the nicked template, so that higher concentrations of these salts are needed before polymerase activity begins to decline. Heparin inhibits initiation but not elongation by wheat germ polymerase. Polymerase can be protected against heparin inhibition by forming binary complexes with the template. The formation of these complexes is reduced at low temperature. The complexes, once formed, decay in the presence of heparin with a half-life of 10--20 min. The number of complexes is highly dependent on the degree of nicking of the template, suggesting that single-strand nicks are the predominant type of site where these heparin-resistant complexes are formed. Our data do not allow us to decide whether or not the presence of nicks plays as decisive a role in the absence of heparin.
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PMID:In vitro transcription by wheat germ ribonucleic acid polymerase II: effects of heparin and role of template integrity. 38 73

The in vivo binding of radioactive N-2-acetylaminofluorene (AAF) and N-hydroxy-2-acetylaminofluorene (N-OH-AAF) to the DNA of rat liver chromatin was examined. The chromatin was fractionated into putative transcriptionally active and inactive fractions by hydrodynamic shearing and subsequent glycerol gradient centrifugation, DNAase II digestion followed by MgCl2 aggregation of transcriptionally inactive chromatin, or mild digestion with micrococcal nuclease. Carcinogens were administered for various times prior to sacrifice. Irrespective of the duration of exposure, no preferential binding of either carcinogen to DNA was detected in any of the fractions prepared by hydrodynamic shearing of DNAase II digestion. When micrococcal nuclease was utilized, a 2-fold increase in carcinogen bound to the DNA of that chromatin fraction containing the smallest molecular weight fragments was detected. These small molecular weight fragments produced by micrococcal nuclease have been postulated to be derived from in vivo transcriptional units. Additionally, when DNAase II was used to probe chromatin from rat livers which had been exposed to a carcinogenic regimen of AAF, no preferential binding of radioactive N-OH-AAF to the DNA of any chromatin fraction was detected.
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PMID:In vivo binding of N-2-acetylaminofluorene and its N-hydroxy derivative to the DNA of fractionated rat liver chromatin. 49 53

Chromatins of four embryonic chick tissues were digested with DNAase II and the MgCl2-soluble and insoluble chromatin fractions were isolated. The MgCl2-soluble fractions displayed a high protein/DNA ratio and enrichment of nascent RNA as compared to the MgCl2-insoluble fractions. The recovery of DNA and protein in the MgC12-soluble chromatin of erythrocytes was much lower than that in the other cell types. The difference is likely to be associated with the low transcriptional activity of the erythrocyte chromatin. In polyacrylamide gels histones appeared to be the predominant protein constituent of the MgCl2-insoluble chromatins. Brain, skin and muscle displayed an apparently similar group of actively labelled nonhistones at 70 000 to 100 000 daltons. These nonhistones were not observed in erythrocytes. The MgCl2-soluble chromatins of erythrocytes, brain, skin and muscle had a prominent group of polypeptides at approx. 40 000 daltons. In all tissues except for erythrocytes the group of proteins was actively labelled. These polypeptides are suggested to be the major structural protein constituent of the MgCl-soluble chromatin.
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PMID:Protein composition of chromatin subfractions prepared from chick embryos. 55 42

Hen oviduct chromatin was digested with DNAase II and two fractions were isolated: MgCl2-insoluble chromatin and MgCl2-soluble chromatin. The former contained 14 and 50% of the total DNA after a digestion time of 3 and 30 min, respectively. The fraction was characterized in sucrose gradients by a peak sedimenting at 11S. In the course of DNAase digestion this fraction lost most of its estrogen receptors as assayed by [3H]estradiol exchange reaction. The specific radioactivity of chromatin was particularly low in the 11S region. The MgCl2-soluble chromatin contained at most 5.1% of the total DNA. In sucrose gradients the fraction displayed peaks at 4S and 14S. After a 30 min DNAase digestion the specific radioactivity of chromatin in this fraction exceeded that of the MgCl2-insoluble fraction 7.7 fold. Material sedimenting at 14 S and at larger S values was enriched in estrogen receptors. The results suggest that estrogen receptors are unevenly distributed on hen oviduct chromain.
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PMID:Distribution of estrogen receptors in hen oviduct chromatin fractions in the course of DNAase II digestion. 83 7

The activity and quantity of deoxyribonucleases in T and B lymphocyte cells isolated from peripheral blood of patients with transplanted kidney were investigated. Twenty three patients with transplanted organ, aged 35 +/- 9.7, treated with cyclosporin A and thirteen individuals after renal transplantation in age 34.8 +/- 6.3 treated conservatively were studied. The enzyme activity was defined as resting DNase activity (DNase 0). Where specifiel the reaction mixture was supplied either with 5 mM MgCl2 (DNaseMg2+) or 1 mM MnCl2 (DNase1 x Mn2+) or 2 mM MnCl2 (DNase2 x Mn2+). Two enzyme groups with molecular mass 32 kDa and 14 to 18 kDa were analyzed. It was evidenced that the nuclease activity in B lymphocyte isolated from patients treated with cyclosporin A after organ transplantation was quite close to the control subjects. On the contrary, the nucleases activity and quantity increased in T lymphocyte of the same patients and increasing in enzymes activity was depending upon haemodialysis period of time prior to organ transplantation. Enzymes activity correlate with clinical parameters typical for kidney transplant rejection. The activity and quantity of nucleases was slightly reduced in both T and B lymphocytes isolated from patients treated conservatively after organ transplantation. The useful of nuclease assay for monitoring of kidney transplant rejection is discussed.
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PMID:[Analysis of the activity of matrix DNA synthesis in the lymphocytes of patients after kidney transplantation and the role of the processes of degradation of DNA-dependent RNA polymerases in the overall cellular nucleolytic activity]. 181 76

The chromatin structure of a transcriptionally active gene coding for 18S-ribosomal RNA in rat cells differing in transcriptional activity (cerebellum neurons and thymocytes) was studied. In the presence of 3 mM MgCl2 nuclease digestion with DNAase I or DNAase II and subsequent blot hybridization analysis revealed that this gene has a completely decondensed chromatin structure in neuronal nuclei. Under the same conditions the 18S ribosomal gene has a partially unfolded chromatin structure in thymocyte nuclei according to the earlier described "nuclease criterion". At 3 mM MgCl2 inactive chromatin of the repeating genomic DNA element has a compact structure which is characterized by a dinucleosomal periodicity of fragmentation with the DNAases and has the same pattern of decompactization after MgCl2 concentration reduction as total chromatin of pigeon erythrocyte nuclei does.
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PMID:[The chromatin structure of transcriptionally active and inactive repetitive nucleotide sequences]. 237 14


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