Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The different species of polyoma virus-spedific RNA molecules present in the cytoplasm of 3T6 cells 30 hr after viral infection have been characterized by molecular hybridization between nonradioactive polyadenlated RNA, fractionated by sedimentation through sucrose-formamide density gradients, and the 32P-labeled separated strands of restriction endonuclease fragments of polyoma DNA. Two relatively abundant RNA molecules, sedimenting at 16S and at 19S, transcribed from the L strand of the viral DNA, as well as a minor 20S species transcribed from the E strand of the DNA, were detected. The most abundant viral transcript, the 16S RNA molecule, was estimated to be complementary to the 22% of the L-strand DNA extending from 47 to 25 map units. The less abundant 19S L DNA strand transcript included all the sequences present in the 16S RNA and mapped between 68 and 25 map units. The minor 20S RNA molecule was tentatively identified as a transcript of the E-strand DNA from the entire early region of the polyoma genome. These three viral RNA molecules together exhaust greater than 95% of the coding capacity of the viral DNA. A small region of the DNA (4-5%), including the origin of DNA replication, does not appear to determine sequences present among the major stable species of vital mRNA.
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PMID:Topography of polyoma virus messenger RNA molecules. 18 Nov 43

Approximately 15% of the polyadenylic acid-containing cytoplasmic RNA labeled from 5 to 7 h after vaccinia virus infection formed intermolecular duplex structures characterized as double-stranded RNA by RNase resistance, density in Cs2SO4, base composition, chromatography on cellulose, and ability to inhibit reticulocyte cell-free protein synthesis. Both sucrose gradient sedimentation and electron microscopic analysis indicated that the double-stranded regions were several hundred to more than a thousand nucleotide base pairs long. The double-stranded RNA, after denaturation, hybridized to approximately 25% of the vaccinia virus genome, whereas total late RNA hybridized to 42%. The finding that the duplex RNA, after denaturation, hybridized to most HindIII restriction endonuclease fragments of vaccinia virus DNA indicated that symmetrical transcription is not confined to the terminal inverted repeat sequence or to one contiguous region of the genome. Although relatively little labeled, early, polyadenylic acid-containing RNA formed RNase-resistant hybrids upon self-annealing, the percentage increased upon addition of unlabeled late RNA, indicating that the latter contains "anti-early" sequences.
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PMID:Intermolecular duplexes formed from polyadenylylated vaccinia virus RNA. 48 Apr 57

Equilibrium density gradient centrifugation in CsCl confirms that DNA synthesized after vaccinia virus infection of HeLa cells is homogeneous in buoyant density and thus in base composition and is similar in this respect to bulk HeLa cell DNA. In contrast, rate sedimentation in alkaline sucrose gradients distinguishes two main classes of virus-induced DNA, neither of which can be equated with cell DNA synthesized in the same cultures prior to infection. The slower sedimenting class of virus-induced DNA co-sediments with DNA from purified virus particles: the second class sediments faster than pre-labelled cell DNA. Heterogeneity of virus-induced DNA does not result from fragmentation of radioactively labelled DNA, virus-mediated breakdown of cell DNA or association with either proteins or polyamines. Both slow and fast sedimenting classes of virus-induced DNA contain sequences complementary to all restriction endonuclease Hind III-specific fragments of the virus genome. The multiple species of DNA synthesized after infection are distinguished further by the effect of ethidium bromide. At a concentration which prevents the formation of infectious progeny virus, this compound inhibits selectively the de novo synthesis of that class of virus-induced DNA which sediments faster in alkaline sucrose gradients.
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PMID:De novo synthesis of two classes of DNA induced by vaccinia virus infection of HeLa cells. 75 58

A polymerase chain reaction (PCR) strategy for differentiating between a vaccine mutant strain and wild-type (WT) strains of Aujesky's disease (pseudorabies) virus (ADV) was evaluated. With this approach, a single virus or a concurrent WT and vaccine virus infection could be distinguished by targeting the genomic alteration within the vaccine strain. PCR primers were designed for a recombinant vaccine virus that has almost all of the WT gX gene replaced by the lacZ gene. One primer, corresponding to a conserved sequence upstream of the altered region, was selected for common use. The differentiating primers were chosen from the unique WT gX and vaccine lacZ gene sequences. The sensitivity of the differential PCR was analyzed using extracted viral DNA and in vitro infected cell lysates. Approximately 10 and between 10 to 100 molecules of WT and vaccine viral DNAs, respectively, could be detected, regardless of the presence or absence of uninfected cell lysates. Detection of viral DNA from in vitro infected cell cultures approximated this level of sensitivity. The specificity of the amplifications was verified by restriction endonuclease analysis and Southern hybridization. Although the vaccine primer pair target was amplified to a lesser degree as compared to the WT primer pair product, utility of the differential PCR was demonstrated using trigeminal nerve ganglia from swine infected with vaccine virus and WT virus. Both viral targets were detected only by their specific primer pair, in either the single or dual infection.
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PMID:Differential polymerase chain reaction for detection of wild-type and a vaccine strain of Aujeszky's disease (pseudorabies) virus. 132 28

Eight strains of Chlamydia psittaci isolated from swine with pneumonia, pleuritis, pericarditis, and enteritis were characterized through analysis of the major outer membrane protein gene ompA by a two-step polymerase chain reaction, by their interactions with cells in culture, and by the morphologic features and ultrastructure of intracellular inclusions. Amplified chlamydial ompA DNA fragments were differentiated by restriction endonuclease digestion. Chlamydial isolates were separated into 2 types on the basis of ompA restriction fragment length polymorphism. Strains of type L71 had finely granular inclusions, whereas those of type 1710S contained pleomorphic reticulate bodies (RB) in the inclusions, which are characteristic of aberrant chlamydial developmental forms. Chlamydial types L71 and 1710S required centrifuge-assisted inoculation for efficient infection of cell cultures. Cultivation in cell culture medium containing cycloheximide increased the numbers of chlamydial inclusions about 1.5-fold. These strains formed few elementary bodies in yolk sac cells of chicken embryos. Ultrastructurally, unique doublet RB were observed, particularly in strains of the ompA type L71. These doublets consisted of 2 RB, bounded by a cytoplasmic membrane, contained within a common cell wall and an extended periplasmic space. Ultrastructural examination of strains of the ompA type 1710S confirmed the aberrant chlamydial developmental forms, but evidence of viral infection of the RB as a cause of these aberrant forms was not found. The strain S45 isolated from intestinal sites of swine was a trachoma restriction fragment length polymorphism type. With the mouse biotype, it represented the second isolate from animals of Chlamydia trachomatis.
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PMID:Biological properties and genetic analysis of the ompA locus in chlamydiae isolated from swine. 135 14

Postoncolytic immunity entails immune reactions acquired through an oncolytic virus infection or through repeated immunizations with viral oncolysates (or virally modified tumor cell membranes) that are valid and operational also against virally not modified tumor cells of the same type. NK cells react to budding virions, induce target cell lysis primarily but not exclusively by the production of granzymes and pore-forming proteins and operate without direction from memory cells. In contrast, immune T cells (including some TIL) are MHC-restricted, act under the direction of memory cells and lyse target cells primarily but not exclusively by the release of lymphotoxin (TNF beta) causing programmed cell death (apoptosis) through endonuclease activation and target cell DNA fragmentation. This author proposes that it is not NK, but the immune T cells that mediate postoncolytic immunity. Oncogene amplification may protect immortalized tumor cells even when expressing peptide antigens through MHC molecules against lymphotoxin-mediated apoptosis; but virally-infected tumor cells releasing budding virions remain susceptible to NK cells. Highly immunogenic viral oncolysates should present both budding virions for NK cells and processed viral and tumoral peptide antigens co-jointly for immune T cells.
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PMID:Viral oncolysates as human tumor vaccines. 166 89

A highly leukemogenic virus (DMBA-LV) induces thymic lymphomas with a very short (40 days) latent period. All induced tumors contain low numbers of new integrated DMBA-LV type-B proviruses and tumorigenicity of DMBA-LV is completely abolished by a monoclonal antibody directed toward an envelope determinant present on a type-B mammary tumor-inducing viral isolate. While the DMBA-LV type-B genome is very highly related to mammary tumor-inducing isolates it does have unique gp52 and p28 proteins as well as unique restriction endonuclease sites. In the present study the target cell specificity of DMBA-LV was contrasted with that of the mammary tumor-inducing isolate MMTV (C3H). The results indicated that infection of CFW/D mice with DMBA-LV could be detected in the thymus only as early as 17 days postinfection and by 40 days postinfection all 40 thymuses examined contained new integrated proviral copies of DMBA-LV. In contrast, when mice were injected intrathymically with MMTV (C3H) virus infection was transiently detected in the thymus only at 28 days postinfection. By 35 and 42 days postinfection there was no indication that virus-infected cells were still present. Analysis of individual thymic lobes following DMBA-LV infection suggested that independent tumors may be initiated in each of the separate lobes. Furthermore, there appeared to be a correlation between the weight of the lobe and the number of new DMBA-LV proviral copies, the larger the lobe the greater the number of newly integrated proviral copies.
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PMID:Characterization of early molecular biological events associated with thymic lymphoma induction following infection with a thymotropic type-B retrovirus. 282 9

An enzyme was isolated from a eucaryotic, Chlorella-like green alga infected with the virus PBCV-1 which exhibits type II restriction endonuclease activity. The enzyme recognized the sequence GATC and cleaved DNA 5' to the G. Methylation of deoxyadenosine in the GATC sequence inhibited enzyme activity. In vitro the enzyme cleaved host Chlorella nuclear DNA but not viral DNA because host DNA contains GATC and PBCV-1 DNA contains GmATC sequences. PBCV-1 DNA is probably methylated in vivo by the PBCV-1-induced methyltransferase described elsewhere (Y. Xia and J. L. Van Etten, Mol. Cell. Biol. 6:1440-1445). Restriction endonuclease activity was first detected 30 to 60 min after viral infection; the appearance of enzyme activity required de novo protein synthesis, and the enzyme is probably virus encoded. Appearance of enzyme activity coincided with the onset of host DNA degradation after PBCV-1 infection. We propose that the PBCV-1-induced restriction endonuclease participates in host DNA degradation and is part of a virus-induced restriction and modification system in PBCV-1-infected Chlorella cells.
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PMID:Restriction endonuclease activity induced by PBCV-1 virus infection of a Chlorella-like green alga. 302 90

Disseminated infection with herpes simplex virus type 2 was identified in two patients 20 days after they had received kidney transplants from the same organ donor. Neither patient had neutralizing antibody to herpes simplex virus before transplantation, and both had herpes simplex virus isolated from surveillance cultures of urine before the onset of clinical symptoms. A clear focus of primary infection was not found in either patient. Analysis of the patients' isolates by DNA restriction endonuclease analysis strongly suggested that the strains were identical. These data implicate the allografts as the source of the viral infection.
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PMID:Transmission of infection with herpes simplex virus by renal transplantation. 302 91

La Crosse virus infection of BHK cells leads to a dramatic shutoff of not only host protein synthesis but also viral protein synthesis later in infection. This shutoff can be accounted for by the loss of the cytoplasmic cellular and viral mRNAs. The induction of mRNA instability requires extensive virus replication, since when cycloheximide is added early in infection the preexisting viral and cellular mRNAs do not decrease upon incubation of the cultures. Pretreatment of the cultures with actinomycin D does not affect the ability of La Crosse virus infection to induce mRNA instability, and examination of the rRNAs shows no evidence of specific degradation due to activation of the interferon-associated latent RNase. The induction of mRNA instability therefore does not appear to operate through an interferon pathway. Viral mRNA synthesis, on the other hand, is not turned off during infection, and the cap-dependent endonuclease involved in viral mRNA initiation may be responsible for the mRNA instability.
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PMID:La Crosse virus infection of mammalian cells induces mRNA instability. 333 45


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