Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.21.3 (deoxyribonuclease)
 1,528 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

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 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

Highly purified, (32)P-labeled type 5 adenovirus was employed to study "uncoating" of viral deoxyribonucleic acid (DNA)-defined as the development of sensitivity to deoxyribonuclease. Viral infectivity and radioactivity adsorbed to KB cells at the same rate, and significant amounts of (32)P did not elute from cells throughout the eclipse period. Kinetic studies of viral penetration, eclipse of infectivity, and uncoating of viral DNA indicated that the three events were closely related temporally, that the rates of each were similar, and that they were completed within 60 to 90 min after infection. Viral penetration, eclipse, and uncoating proceeded normally under conditions which blocked protein synthesis, but they did not occur at 0 to 4 C. Neither viral DNA nor viral protein was degraded to acid-soluble material during the eclipse period. The nature of adenovirus DNA was studied after it was converted intracellularly from deoxyribonuclease-resistant to deoxyribonuclease-susceptible. Intact virions centrifuged in sucrose gradients had a sedimentation coefficient of approximately 800, and viral DNA sedimented as a particle of about 30S. Infection of KB cells with purified (32)P-labeled virus yielded deoxyribonuclease-susceptible viral nucleic acid which was in particles with sedimentation coefficients of 350 to 450S, i.e., greater than 10 times faster than DNA obtained from purified virions which had been disrupted by exposure to pH 10.5. When the DNA from disrupted virions was mixed with cell lysates, its sedimentation characteristics were essentially unchanged by the presence of cellular material.
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PMID:Intracellular uncoating of type 5 adenovirus deoxyribonucleic acid. 562 82

Infection of human embryonic kidney (HEK) cell cultures with adenovirus types 2 or 12 resulted in an initial drop in the rate of incorporation of (3)H-thymidine into deoxyribonucleic acid (DNA) during the early latent period of virus growth, followed by a marked rise in label uptake. It was shown by cesium chloride isopycnic centrifugation that, after adenovirus 2 infection, there was a decrease in the rate of incorporation of thymidine into cellular DNA. Moreover, DNA-DNA hybridization experiments revealed that, by 28 to 32 hr after infection with either adenovirus 2 or 12, the amount of isolated pulse-labeled DNA capable of hybridizing with HEK cell DNA was reduced by approximately 60 to 70%. Autoradiographic measurements showed that the inhibition of cellular DNA synthesis was due to a decrease in the ability of an infected cell to synthesize DNA. The adenovirus-induced inhibition of host cell DNA synthesis was not due to degradation of cellular DNA. (3)H-thymidine incorporated into cellular DNA at the time of infection remained acid-precipitable, and labeled material was not incorporated into viral DNA. Furthermore, when zone sedimentation through neutral or alkaline sucrose density gradients was employed, no detectable change was observed in the sedimentation rate of this cellular DNA at various times after infection with adenovirus 2 or 12. In addition, there was no increase in deoxyribonuclease activity in cells infected with either virus. Cultures infected for 38 hr with adenovirus 2 or 12 incorporated three to four times as much (3)H-uridine into ribonucleic acid (RNA) as did non-infected cultures. Furthermore, the net RNA synthesized by infected cultures substantially exceeded that of control cultures. The activity of thymidine kinase was induced, but there was no stimulation of uridine kinase.
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PMID:Kinetics of nucleic acid synthesis in human embryonic kidney cultures infected with adenovirus 2 or 12: inhibition of cellular deoxyribonucleic acid synthesis. 580 81

Infection of Escherichia coli containing the type I restriction enzyme EcoKI by bacteriophage T7 0.3 mutants leads to restriction during the late stages of genome entry and during DNA replication. Patterns of cleavage in vivo suggest that some cutting occurs near the midpoint of two recognition sites, consistent with the idea that EcoKI translocates DNA bidirectionally through itself and cuts when two enzyme molecules collide. Rapid ejection of a 0.3(+) T7 genome from a bacteriophage lambda particle results in degradation of the infecting DNA by EcoKI, showing that the normal T7 DNA translocation process delays restriction. A unique recognition site inserted at the genomic left end allows EcoKI to function as a molecular motor and to translocate the remaining 39 kilobases of T7 DNA into the cell.
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PMID:Translocation and specific cleavage of bacteriophage T7 DNA in vivo by EcoKI. 1053 39