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)

Infection of Escherichia coli with bacteriophage T7 results in an inhibition of the host exonuclease V (recB, C DNase) activity. This inhibition is not observed when cells are infected in the presence of chloramphenicol or with a gene 1 mutant. The protein responsible for the inhibition of exonuclease V has been partially purified from T7-infected cells. The protein which does not possess nuclease or ATPase activity can inhibit all nucleolytic activities associated with exonuclease V. The protein does not, however, inhibit the DNA-dependent ATPase activity associated with exonuclease V. The inhibitory protein has a molecular weight of about 12,000, as determined from sedimentation analysis in glycerol gradients.
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PMID:Partial purification and properties of a bacteriophage T7 inhibitor of the host exonuclease V activity. 12 51

Infection by bacteriophage T4 has previously been shown to cause a rapid inhibition of the host recBC DNase, an ATP-dependent DNase that is required for genetic recombination in Escherichia coli. We report here the partial purification of a protein ("T4 rec inhibitor") from extracts of T4-infected cells and some characteristics of the in vitro inhibition reaction with purified inhibitor and recBC nuclease. This inhibitory activity could not be purified from extracts of uninfected E. coli. Both the ATP-dependent exonuclease and DNA-dependent ATPase activities of recBC DNase are inhibited by T4 rec inhibitor. Experiments suggest that the inhibitor interacts with the nuclease in a stoichiometric manner. The biological significance of this inhibition is discussed with respect to control reactions in phage-infected cells.
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PMID:Postinfection control by bacteriophage T4 of Escherichia coli recBC nuclease activity. 13 May 1

Lysogenization of nonlysogenic strains of Staphylococcus aureus was performed with two different bacteriophages, LS1 and LS2, that were unable to plaque on any of the strains of S. aureus tested. Infection of recipient strains was achieved when protoplasts were inoculated with LS1 or LS2 or when bacterial cultures were simultaneously inoculated with a virulent phage together with LS1 or LS2. Lysogenization was demonstrated by changes in phenotypic characters of the host strain and by liberation of bacteriophages from the modified strains as shown by electron microscopic examination. The lysogenic strains differed from the host strains by the following characters: they were coagulase, deoxyribonuclease, and lipase negative; they were untypable by the basic set of phages; they did not ferment mannitol under anaerobic conditions; and they produced only l-(+)-lactic acid by glucose fermentation. Their cell walls contained less glycine and concomitantly more serine than those of the host strains. Furthermore, they were devoid of protein A. Conversely, some antigenic factors as well as the presence of ribitol in the cell wall teichoic acid, indicated a parental relationship between the host strains and the derived lysogenic ones. Phages LS1 and LS2 could be excluded from the lysogenic strains by invading phages, and the revertant nonlysogenic strains recovered all of the characteristics of the initial host strains. It was thus concluded that the phenomenon described was due to lysogenic conversion. The origin of phages LS1 and LS2 is discussed.
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PMID:Lysogenic conversion for multiple characters in a strain of Staphylococcus aureus. 14 Aug 62

Infection of BALB/c mouse cells with UV-irradiated herpes simplex virus (HSV) types 1 and 2 resulted in activation of a xenotropic type C virus detected by infectious center formation in permissive rat cells. The levels of type C virus activated by HSV were related to the UV dose and the multiplicity of infection used. The ability of HSV to activate type C virus was eliminated by heat-inactivation and by neutralization with specific antiserum against HSV, but was not affected by purification or treatment with DNase and RNase. Maximum levels of type C virus in the cells and medium were observed within 1 day after HSV infection, and the levels returned to control cell values within 3-4 days. The possible significance of these findings with respect to the putative oncogenic potential of HSV is discussed.
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PMID:Activation of an endogenous mouse type C virus by ultraviolet-irradiated herpes simplex virus types 1 and 2. 17 17

A subnuclear fraction has been isolated from HeLa S3 nuclei after treatment with high salt buffer, deoxyribonuclease, and dithiothreitol. This fraction retains the approximate size and shape of nuclei and resembles the nuclear matrix recently isolated from rat liver nuclei. Ultrastructural and biochemical analyses indicate that this structure consists of nonmembranous elements as well as some membranous elements. Its chemical composition is 87% protein, 12% phospholipid, 1% DNA, and 0.1% RNA by weight. The protein constituents are resolved in SDS-polyacrylamide slab gels into 30-35 distinguishable bands in the apparent molecular weight range of 14,000 - 200,000 with major peptides at 14,000 - 18,000 and 45,000 - 75,000. Analysis of newly synthesized polypeptides by cylindrical gel electrophoresis reveals another cluster in the 90,000-130,000 molecular weight range. Infection with adenovirus results in an altered polypeptide profile. Additional polypeptides with apparent molecular weights of 21,000, 23,000, and 92,000 become major components by 22 h after infection. Concomitantly, some peptides in the 45,000-75,000 mol wt range become less prominent. In synchronized cells the relative staining capacity of the six bands in the 45,000-75,000 mol wt range changes during the cell cycle. Synthesis of at least some matrix polypeptides occures in all phases of the cell cycle, although there is decreased synthesis in late S/G2. In the absence of protein synthesis after cell division, at least some polypeptides in the 45,000-75,000 mol wt range survive nuclear dispersal and subsequent reformation during mitosis. The possible significance of this subnuclear structure with regard to structure-function relationships within the nucleus during virus replication and during the life cycle of the cell is discussed.
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PMID:Nuclear matrix of HeLa S3 cells. Polypeptide composition during adenovirus infection and in phases of the cell cycle. 83 Jun 54

The Epstein-Barr virus (EBV) alkaline deoxyribonuclease (DNase) was inserted into the baculovirus Autographa californica nuclear polyhedrosis virus (AcMNPV). Infection of the insect cell line Spodoptera frugiperda (SF9) with the recombinant virus led to the expression of an enzymatically active alkaline DNase. The recombinant EBV alkaline DNase was highly soluble, and the recombinant baculovirus produced approximately 10-20 mg of EBV DNase per 1 X 10(9) cells. The recombinant enzyme activity was neutralized by specific antisera to the EBV DNase and was recognized by these sera in Western blot analysis and immunofluorescence tests. The recombinant EBV DNase was neutralized by these sera from patients with nasopharyngeal carcinoma and chronic infectious mononucleosis. Western blot analysis using these patients' sera showed that IgG and IgA antibodies to the EBV DNase could be readily detected.
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PMID:High-level expression of the Epstein-Barr virus alkaline deoxyribonuclease using a recombinant baculovirus: application to the diagnosis of nasopharyngeal carcinoma. 184 61

Infection of HSB-2 cells with human herpesvirus 6 (HHV6) results in an approximately 51-fold increase in the level of DNA polymerase activity and a 4.44-fold increase in the level of DNase activity when compared to mock-infected cells. There was no increase in thymidine kinase, uracil-DNA glycosylase, or deoxyuridine triphosphate nucleotidohydrolase activities in the infected cells. The HHV6-induced DNase and DNA polymerase activities could be distinguished from their normal cellular counterparts on the basis of immunological specificities and in the case of DNA polymerase based upon differences in electrophoretic migration. Serological studies also demonstrated reactivity of the antisera not only for HHV6 but also for Epstein-Barr virus.
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PMID:Demonstration of the human herpesvirus 6-induced DNA polymerase and DNase. 255 71

Infection of Vero cells with African swine fever (ASF) virus resulted in a marked increase of DNase active on single-stranded DNA (ss-DNase). No increase was observed for double-stranded DNA-specific nuclease activity. In contrast to uninfected cell ss-DNase, which has a pH optimum at pH range 8.5-9, virus-induced ss-DNase is most active at pH 7. Differences in sensitivity to several ions and other modifications of the reaction mixture and considerable difference in reaction kinetics suggest that the increase in nuclease activity is due to a new virus-induced enzyme. This is strengthened by the fact that anti-ASF virus antiserum inhibits the activity of ss-DNase from infected cells but not from uninfected cells. Exclusion chromatography of the digests shows that virus-specific ss-DNase is exclusively or predominantly an endonuclease. The increase in nuclease activity of infected cells is proportional to the multiplicity of infection. Virus-specific ss-DNase is synthesized at late times after infection and its synthesis is dependent on viral DNA replication since it is not induced when infected cells are treated with cytosine arabinoside. Most of ss-DNase activity in infected cells is associated to an insoluble cytoplasmic fraction, presumably virosomes. The enzyme can also be detected in partially stripped purified virions which hydrolyze 6.9 ng DNA per microgram viral protein.
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PMID:Single-stranded deoxyribonucleic acid nuclease induced by African swine fever virus and associated to the virion. 377 99

Infection of the bursa of Fabricius and chicken embryo fibroblast cell cultures with avian infectious bursal disease virus resulted in production of a number of virus-induced antigens. The antigens were specific, forming three precipitin lines by immunodiffusion with antiserum (designated PA-1, -2, and -3). To separate immunoprecipitin from the remaining viral particles, two (PA-1 and PA-3) were partially purified by subjection to two cycles of diethylaminoethyl-cellulose chromatography and filtration through a column of Sephadex G-150 gel. The precipitating antigen, PA-1, was found to migrate most slowly through the agar gel, remaining serologically active after treatment with heating (56 C for 1 h), trypsin, lipolytic solvents, deoxyribonuclease, and ribonuclease. Its density was 1.27 g/ml. Morphologically the antigen displayed a doughnut-shaped structure 8 to 12 nm in size. PA-3 migrated most rapidly through the agar gel. It was destroyed by treatment with heating and trypsin but not with lipolytic solvents, deoxyribonuclease, and ribonuclease. Density was about 1.25 g/ml. This suggests that the antigen is a part of viral structural components. PA-2 migrated through agar gel at a rate between that of PA-1 and PA-3. Because of its low concentration, PA-2 was not further characterized.
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PMID:Some properties of precipitating antigens associated with infectious bursal disease virus. 421 58

Infection of Salmonella typhimurium with phage P22 causes a decrease in the activity of host deoxyribonuclease which degrades single-stranded deoxyribonucleic acid (DNA). This decrease is reversed when the infecting phage is P22c(+); it is not reversed if the infecting phage kills the cell. The decrease does not occur in infections with P22ts25.1 (which only adsorbs and injects DNA) or in infections of a lysogen by a nonvirulent phage. It does occur, however, after infections with other phages which are blocked in phage DNA synthesis. Inhibiting protein synthesis with chloramphenicol does not in itself cause the decrease in uninfected cells, but it does prevent infected cells from showing this effect.
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PMID:Inhibitory effect of bacteriophage P22 infection on host cell deoxyribonuclease activity. 455 64


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