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:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A ribonucleoprotein complex (TNP) containing an active RNA polymerase was isolated from purified vesicular stomatitis virus particles. The TNP sedimented through a sucrose gradient as a single band and appeared under the electron microscope as discrete long filaments in a spiral configuration. TNP contained one major and two minor polypeptides, but not the polypeptides associated with the outer coat of vesicular stomatitis virus. BHK-21 clone 13 cells could be infected with TNP, yielding infectious virus particles.
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PMID:Isolation of an infectious ribonucleoprotein from vesicular stomatitis virus containing an active RNA transcriptase. 434 29

The initiation of RNA transcription by the virion-bound RNA transcriptase of vesicular stomatitis virus has been examined. Multiple initiation sequences have been observed, two of which have been characterized (pppApCpGp... and pppGpCp...) suggestive of a transcription process which can start at different sites along the template RNA. By the use of sequential labeling techniques and exonucleases, it has been determined that there is a 5' to 3' direction of product RNA synthesis.
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PMID:Initiation and direction of RNA transcription by vesicular stomatitis virus virion transcriptase. 434 90

The wild-type strain of vesicular stomatitis virus (VSV) contains in its complete virion (VSV-1, B particles) a minus strand RNA. The principle defective particle of the wild-type strain (VSV-111, T particles) contains a shorter minus strand, homologous to part of the VSV-1 genome. Neither virion contains any detectable complementary (plus) strand RNA. In contrast, a preparation of a heat-resistant (HR) strain of VSV containing defective virions was found to contain both plus (21%) and minus strand RNA, present in several distinct size classes. It was found that the RNA in the HR virion preparation was at least 94% single-stranded and principally (96%) in ribonucleoprotein complexes. On extraction the plus and minus strand RNA species partially annealed to give a population of double- and multistranded RNA species. A small amount of RNA polymerase activity was associated with the HR defective virus preparation.
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PMID:Complementary RNA species isolated from vesicular stomatitis (HR strain) defective virions. 435 60

T-particle-free stocks of temperature-sensitive mutants representing the four Glasgow complementation groups of the Indiana serotype of vesicular stomatitis virus were used to study RNA synthesis at the permissive and nonpermissive temperatures of 31 and 39 C, respectively. Mutants selected from the four Glasgow complementation groups were characterized on the basis of particle and ribonucleoprotein formation. Intracellular RNAs were further characterized by polyacrylamide gel electrophoresis. ts G22 (group II) and ts G41 (group IV), previously characterized as RNA negative at the nonpermissive temperature, synthesized low levels of RNA which could not be attributed to contaminating levels of revertants. Furthermore, the levels of synthesis could not be reduced by the addition of cycloheximide. These data suggest that ts G22 (group II) and ts G41 (group IV) contain a thermally stable, virion-encapsidated transcriptase, but fail to amplify RNA synthesis due to a thermally labile function presumably necessary for the synthesis of viral RNA. ts G31, a group III mutant, synthesized intracellular RNA at amplified levels at the nonpermissive temperature. Intracellular ribonucleoprotein complexes were isolated in copious amounts; however, no particles corresponding in size to finished virions were observed. These data suggest a thermally labile maturation factor or envelope associated structural protein to be defective in ts G31 (group III). ts G11 (group 1) showed no detectable RNA synthesis at the nonpermissive temperature. These data suggest ts G11 (group I) contains a thermally labile component involved in early transcription. This group may contain a number of mutants defective in different components of the transcription apparatus, which may not complement in vivo because of the physical improbability of subunit exchange between virion particles of the incoming inoculum.
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PMID:RNA synthesis in temperature-sensitive mutants of vesicular stomatitis virus. 435 55

The synthesis of viral RNA by wild-type vesicular stomatitis virus (L(1)VSV) and a small, plaque-size mutant (S(2)VSV) was studied in vitro and in chicken embryo (CE) and mouse L-cell cultures. Virus-specific RNA synthesized in CE or L cells infected with either L(1) or S(2)VSV at low multiplicity was of the same size classes, 12 to 15S, 28S, and 38S. The major differences were in the proportion of RNA produced of each size class. L(1)VSV always synthesized larger proportions of 38S RNA, and S(2)VSV produced larger proportions of 12 to 15S RNA. Both S(2) and L(1)VSV exhibited RNA transcriptase activity in vitro and in cell culture. The products of the in vitro reaction were the same, 12 to 15S for both. The products of the virion-associated transcriptase in CE or L-cell cultures in the presence of cycloheximide were also the same for both viruses but differed from the in vitro products in that 28S and 12 to 15S RNA were made. The effects of addition of cycloheximide at various times after infection demonstrated that new protein synthesis is required early (0-2 h) for both S(2) and L(1)VSV to initiate and maintain the normal rate of viral RNA synthesis. However, the overall rate of RNA synthesis in L(1)VSV infections became independent of protein synthesis after 2 h whereas the rate in S(2)VSV infections did not. With either virus, synthesis of 38S RNA did not occur in the absence of protein synthesis. Moreover, continuous 38S RNA production required continuous protein synthesis. Production of 38S RNA ceased within 30 min after addition of cycloheximide to S(2) (-) or L(1)VSV-infected CE or L cells that had already begun to synthesize the 38S form. The cycloheximide-induced cessation of 38S RNA synthesis was accompanied by a marked increase in production of 12 to 15S and 28S RNA in L(1)VSV-infected cells, but no increase in synthesis of small RNA species occurred in S(2)VSV-infected cells.
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PMID:RNA synthesis by vesicular stomatitis virus and a small plaque mutant: effects of cycloheximide. 435 30

The endogenous transcriptase present in purified vesicular stomatitis (VS) virions was solubilized with a Triton X-100 high-salt solution. The polymerase activity was purified on glycerol gradients and by phosphocellulose column chromatography; the viral proteins present in the active enzyme fractions were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis. It was demonstrated that L protein, but not NS protein, was required for in vitro RNA synthesis on the VS viral nucleocapsid template. Solubilized L protein rebinds to the ribonucleoprotein template when the transcription complex is reconstituted, and the RNA synthesized in vitro by purified L protein hybridizes to virion RNA. Cyanogen bromide peptide fingerprints indicate that the large L protein is a unique polypeptide chain. It is concluded that the L protein functions as the transcriptase, and the nucleocapsid NS protein is not essential for in vitro RNA synthesis.
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PMID:L protein requirement for in vitro RNA synthesis by vesicular stomatitis virus. 435 10

The RNA synthesized in vitro by the virion-associated RNA-instructed RNA polymerase of purified vesicular stomatitis virus contains polyadenylate sequences. These have been demonstrated by their partial resistance to pancreatic and T(1) ribonucleases and their capacity to bind to poly(U) filters and oligo(dT)-cellulose. The polyadenylate sequences range in apparent size from 50 to 200 bases, similar to the size of the poly(A) in mRNA from vesicular stomatitis virus-infected cells. Possible mechanisms of polyadenylylation of the in vitro RNA product are discussed.
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PMID:In vitro synthesis of RNA that contains polyadenylate by virion-associated RNA polymerase of vesicular stomatitis virus. 435 80

The ribonucleoprotein-dependent RNA transcriptase in vesicular stomatitis B virions of four temperature-sensitive (ts) mutants belonging to complementation group I was analyzed in vitro at permissive (31 C) and restrictive (39 C) temperatures. The RNA-synthesizing activity of all four ts mutants was more labile at 39 C than was the transcriptive activity of wild-type (wt) virions. In order to locate the temperature-sensitive transcription defect in the mutants, wt and ts mutant virions were fractionated by Triton X-100-high salt solubilizer into a sedimentable ribonucleoprotein template and a nonsedimentable enzyme fraction, each of which alone had little or no transcriptive activity. The template- and enzyme-containing fractions of wt virions were then tested for their capacity to restore transcriptive activity at 39 C to corresponding template and enzyme preparations of ts mutant virions. Recombination of wt template and ts enzymes resulted in no significant restoration of capacity to synthesize RNA at restrictive temperature. In contrast, transcriptive function at 39 C was reconstituted by recombining the wt enzyme with the template component of ts mutants. It appears, therefore, that the enzyme, rather than the template, is the temperature-sensitive component of the transcription complex of group I vesicular stomatitis virus mutants.
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PMID:Location of the transcription defect in group I temperature-sensitive mutants of vesicular stomatitis virus. 435 28

The presence of a virion-associated RNA-dependent RNA polymerase in five serologically distinct rhabdovirus isolates (vesicular stomatitis virus [VSV] Indiana, VSV New Jersey, Cocal, Chandipura, and Piry viruses) has been demonstrated. The enzyme for each virus has been shown to be a transcriptase capable of synthesizing in vitro RNA which is complementary to the viral genome. By sequence analyses it has been shown that, for each rhabdovirus, transcription is multiply initiated with specific 5' nucleotide sequences. The results indicate that, for all five viruses, the initiation of transcription involves similar sequences (e.g., pppApCpGp..., pppGpCp..., and possibly one or two other sequences), suggesting relatedness and some genome conservation among these viruses.
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PMID:RNA transcription by the virion polymerases of five rhabdoviruses. 436 67

Heterologous viral interference is induced by Sindbis virus against vesicular stomatitis virus (VSV) in a manner analogous to intrinsic interference with Newcastle disease virus replication. Interference in both systems (i) depends upon early expression of the inducing virus genome, (ii) shows similar kinetics of induction, (iii) does not involve interferon action, and (iv) appears to be manifest as an all-or-none effect. VSV can be added to the list of viruses blocked by intrinsic interference. Sindbis virus-induced intrinsic interference with VSV replication is not mediated through homotypic interference by defective interfering particles; rather, T-particle and B-particle synthesis is inhibited. Significantly, intrinsic interference has no effect on primary transcription directed by the virion-associated transcriptase in VSV-challenged cells. However, Sindbis virus appears to induce interference with the VSV-RNA synthesized subsequent to primary transcription, namely, that which is dependent on protein synthesis. Thus, the target of intrinsic interference appears to be a reaction subsequent to primary transcription but prior to the appearance of protein synthesis-dependent VSV RNA, secondary transcription.
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PMID:Mechanism of Sindbis virus-induced intrinsic interference with vesicular stomatitis virus replication. 436 26


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