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:3.1.31.1 (micrococcal nuclease)
2,818 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

The carbocyclic analog of 2'-deoxyguanosine (CdG) is active against herpes simplex virus (HSV), human cytomegalovirus, and human hepatitis-B virus. In order to understand the mechanism of action of this compound against HSV, we have evaluated (a) the incorporation of [3H]CdG into viral and host DNA in HEp-2 cells infected with HSV and (b) the interaction of the 5'-triphosphate of CdG (CdG-TP) with the HSV DNA polymerase and human DNA polymerases alpha, beta, and gamma (EC 2.7.7.7). Incubation of HSV-1-infected HEp-2 cells with [3H]CdG resulted in the incorporation of CdG into both the HSV and the host cell DNA. These results indicated that CdG-TP was used as a substrate for HSV DNA polymerase and for at least one of the cellular DNA polymerases. Degradation of both viral and host DNA with micrococcal nuclease and spleen phosphodiesterase indicated that CdG was incorporated primarily into internal positions in both DNAs. The viral DNA containing CdG sedimented in neutral and alkaline sucrose gradients in the same way as did viral DNA labeled with [3H]thymidine, indicating that the HSV DNA containing CdG was similar in size to untreated HSV DNA. CdG-TP was a competitive inhibitor of the incorporation of dGTP into DNA by the HSV DNA polymerase (Ki of 0.35 microM) and the human DNA polymerase alpha (Ki of 1 microM). CdG-TP was not a potent inhibitor of either DNA polymerase beta or gamma. Using DNA-sequencing technology, CdG-TP was found to be an efficient substrate for HSV DNA polymerase. Incorporation of CdG monophosphate (CdG-MP) into the DNA by HSV DNA polymerase did not interfere with subsequent chain extension. These results suggested that the antiviral activity of CdG was due to its incorporation into the DNA and subsequent disruption of viral functions. In contrast, CdG-TP was not as good as dGTP as a substrate for DNA synthesis by DNA polymerase alpha, and incorporation of CdG-MP by DNA polymerase alpha inhibited further DNA chain elongation.
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PMID:Incorporation of the carbocyclic analog of 2'-deoxyguanosine into the DNA of herpes simplex virus and of HEp-2 cells infected with herpes simplex virus. 131 7

Micrococcal nuclease digestion technique in combination with spot-blotting hybridization have been used for the characterization of latent Herpes simplex virus type 1 (HSV-1) DNA in mouse brainstems. Two kinds of samples were used i.e. undigested DNA from mouse brainstems and DNA after prolonged digestion (i.e. for 30 minutes) with micrococcal nuclease from the same source. Each sample contained 5 micrograms of DNA (concentration was measured after digestion with micrococcal nuclease and isolation of DNA). Two kinds of probes were used: -virus specific probe, -host cellular probe. In the performed experiments, we observed the increased susceptibility of latent HSV-1 DNA for micrococcal nuclease digestion, comparing it to host DNA, which may reflect differences in protection of latent viral DNA by nuclear proteins and also may be associated with existing limited transcription of HSV-1 genome during latency.
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PMID:Characterization of herpes simplex virus type 1 DNA during latent infection in mice. 166 5

The virion host shutoff (vhs) gene of herpes simplex virus encodes a virion polypeptide that induces degradation of host mRNAs at early times and rapid turnover of viral mRNAs throughout infection. To better investigate the vhs function, an in vitro mRNA degradation system was developed, consisting of cytoplasmic extracts from HeLa cells infected with wild-type herpes simplex virus type 1 or a mutant encoding a defective vhs polypeptide. Host and viral mRNAs were degraded rapidly in extracts from cells productively infected with wild-type herpes simplex virus type 1 but not in extracts from mock-infected cells or cells infected with the mutant vhs1. In contrast, 28S rRNA was stable in all three kinds of extract. Accelerated turnover of host mRNAs was also observed in extracts from cells infected with wild-type virus in the presence of dactinomycin, indicating that the activity was induced by a structural component of the infecting virions. The in vitro vhs activity was inactivated by heat or proteinase K digestion but was insensitive to brief treatment of the extracts with micrococcal nuclease. It was not inhibited by placental RNase inhibitor, it exhibited a strong dependence upon added Mg2+, it was active at concentrations of K+ up to 200 mM, and it did not require the components of an energy-generating system. In summary, the in vitro mRNA degradation system appears to accurately reproduce the vhs-mediated decay of host and viral mRNAs and should be useful for studies of the mechanism of vhs action.
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PMID:In vitro mRNA degradation system to study the virion host shutoff function of herpes simplex virus. 184 79

To investigate the role of the herpes simplex virus origin-binding protein (UL9) in the initiation of DNA replication, we have examined the effect of UL9 binding on the structure of the viral origin of replication. UL9 loops and alters the DNA helix of the origin regardless of the phasing of the binding sites. DNase I and micrococcal nuclease footprinting show that UL9 binds two sites in the origin and loops the AT-rich DNA between them independent of the topology of the DNA. KMnO4 and dimethyl sulfate footprinting further show that UL9 alters the DNA helix in the AT region. In contrast to the looping reaction, however, helical distortion requires the free energy of supercoiled DNA. UL9 also loops and distorts the origin DNA of a replication-defective mutant with a 6-bp insertion in the AT region. Because the helical distortion of this mutant DNA is different from that of functional origins, we conclude that an imperfect tertiary structure of the mutant DNA may contribute to its loss of replication function.
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PMID:Herpes simplex virus origin-binding protein (UL9) loops and distorts the viral replication origin. 185 78

The nucleoprotein organization of herpes simplex virus type 1 (HSV-1) DNA during productive infection was analyzed using staphylococcal nuclease. Both prior to and during the genome replication phase of infection, digestion of nuclei revealed two readily discernible forms of viral DNA, resistant and sensitive. The identity of these forms was established by the use of a variety of assays, including velocity sedimentation, nucleic acid hybridization and restriction endonuclease digestion and by employing temperature sensitive (ts) mutants impaired in either DNA replication or encapsidation of progeny DNA. Thus, nuclease resistant DNA was derived from encapsidated unit length genomes while sensitive DNA represented digestion products of replicating viral genomes. Importantly, no evidence was obtained for the arrangement of either parental or progeny viral DNA in nucleosomes. These findings are discussed with regard to the nucleoprotein structure of replicating viral DNA.
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PMID:Intracellular organization of herpes simplex virus type 1 DNA assayed by staphylococcal nuclease sensitivity. 216 12

Latent herpes simplex virus type 1 DNA has a nucleosomal structure similar to that of cellular chromatin, as determined by micrococcal nuclease digestion. All of the major regions, including the transcriptionally active region of the genome, were found to be associated with nucleosomes. Such a chromatin structure is likely to be an important element in the control of herpes simplex virus type 1 gene expression during latency.
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PMID:During latency, herpes simplex virus type 1 DNA is associated with nucleosomes in a chromatin structure. 253 15

After corneal inoculation, herpes simplex virus type 1 replicates in the mouse eye, trigeminal ganglia, and brainstem, producing first an acute and then a latent infection. Previous work from this laboratory focused on the structure of the viral DNA in this system. We have now examined the structure of the viral genome at the chromosome level by using micrococcal nuclease digestion. Studies with disaggregated cell preparations made from the brainstems of acutely infected mice show that the majority of the viral DNA is in a nonnucleosomal form; however, a nucleosomelike fraction was also consistently detected. A similar result was obtained for viral DNA in herpes simplex virus type 1-infected C1300 (clone NA) neuroblastoma cells (a neuronal cell line).
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PMID:Chromosomal organization of the herpes simplex virus genome during acute infection of the mouse central nervous system. 301 40

Micrococcal nuclease digestion was used to probe the structures in which herpes simplex virus type I (HSV-I) DNA is found during virus replication. Parental DNA, progeny DNA and DNA in nucleocapsids were analysed. Parental DNA was examined after infection of Vero cells with 32P- or 3H-thymidine-labelled HSV-I. Progeny DNA was examined after HSV-I-infected Vero cells were pulse-labelled with 3H-thymidine during HSV-I DNA synthesis. In both cases, nuclei were isolated and digested with micrococcal nuclease. Digestion products were analysed by agarose or polacrylamide gel electrophoresis (PAGE). Most parental DNA remained as intact molecules. However, a small amount was degraded into fragments which were heterogeneous in size or the size of nucleosomal cell DNA. These two classes of fragments were also produced upon digestion of progeny DNA. The heterogeneous fragments and nucleosomal fragments comprised major and minor fractions, respectively, of digested progeny DNA. When digested DNA from HSV-I-infected cells was transferred from composite polyacrylamide-agarose gels to diazobenzyloxymethyl paper, nucleosomal fragments hybridized to 32P-labelled HSV-I DNA as well as to 32P-labelled Vero cell DNA.. Therefore, nucleosomal fragments contained HSV-I DNA sequences. HSV-I DNA in nucleocapsids was analysed by micrococcal nuclease digestion after nucleocapsids were disrupted with PH 9.3 buffer, pyridine, Sarkosyl or NcCl/urea. Only fragments of heterogeneous size were produced. Thus, HSV-I DNA is found predominantly in structures other than nucleosomes during virus replication.
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PMID:The structure of herpes simplex virus type 1 DNA as probed by micrococcal nuclease digestion. 625 37

Mouse thymidine kinase negative (tk-) L-cells were cotransformed with two different kappa light chain genes (cloned from mouse myeloma) and the tk gene from Herpes simplex virus I. (Transformation is defined as change in the genotype by introduction of foreign DNA.) About 80% of the tk+ -transformants contained varying amounts of transferred kappa light chain sequences, one transformant about 150 copies per genome. The transferred immunoglobulin genes appear to be organized in a nucleosomal substructure, as deduced from digestion experiments with micrococcal nuclease. In situ hybridization experiments revealed, that the transferred genes are not distributed randomly across the chromosomes of the recipient cell. Instead they are clustered at one or a few chromosomal locations.
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PMID:Localization in mouse-L-Cell chromosomal sites of transferred immunoglobulin genes. 628 Sep 34


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