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

---

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

A full-length cDNA copy of the phosphoprotein (NS) mRNA of vesicular stomatitis virus (New Jersey serotype) was inserted into pGEM4 vector downstream of the promoter for bacteriophage SP6 RNA polymerase. Transcription of the cDNA in vitro resulted in the synthesis of NS mRNA, which was subsequently translated into NS protein in a cell-free rabbit reticulocyte system. The biological activity of the expressed NS protein was demonstrated by in vitro synthesis of mRNA by transcription-reconstitution with purified viral L protein and N-RNA template. Deletion mapping of the NS gene defined a specific domain between amino acid residues 213 and 247, which was essential for in vitro transcription. Removal of the COOH-terminal 21 amino acids, on the other hand, did not have a significant effect on transcription. This domain appears to be involved in efficient binding of NS protein to the N protein-RNA template.
...
PMID:Identification of a domain within the phosphoprotein of vesicular stomatitis virus that is essential for transcription in vitro. 302 53

Twenty-five spontaneous temperature-stable revertants of four different temperature-sensitive (ts) M protein mutants (complementation group III: tsG31, tsG33, tsO23, and tsO89) were sequenced and tested for their ability to inhibit vesicular stomatitis virus RNA polymerase activity in vitro. Consensus sequences of the coding region of each M protein gene were determined, using total viral RNA as template. Fifteen different sequences were found among the 25 revertants; 14 differed from their ts parent by a single amino acid (one nucleotide), and 1 differed by two amino acids (two nucleotides). Amino acids were altered in various positions between residues 64 and 215, representing over 60% of the polypeptide chain. Resequencing of the Glasgow and Orsay wild types and the four ts mutants confirmed previously published differences (Y. Gopalakrishana and J. Lenard, J. Virol., 56:655-659, 1985), and one or two additional differences were found in each. The relative charges of the revertant M proteins, as determined by nonequilibrium pH gradient electrophoresis, were consistent with the deduced sequences in every case. The ability of each revertant M protein to inhibit the RNA polymerase activity of nucleocapsids prepared from its parent ts mutant was also tested. Only 13 of the 25 revertants had M protein with high (wild type-like) polymerase-inhibiting activity, while 5 had low (ts-like) activity, and 7 had intermediate activity, demonstrating that this property is not an essential concomitant of the temperature-stable phenotype. It is concluded that the high reversion frequency observed for these mutants arises from a very high incidence of pseudoreversion, i.e., many different molecular changes can repair the ts phenotype.
...
PMID:Phenotypic revertants of temperature-sensitive M protein mutants of vesicular stomatitis virus: sequence analysis and functional characterization. 302 58

Indomethacin blocks the biosynthesis of vesicular stomatitis virus (VSV) at the level of primary transcription, RNA replication, and protein synthesis (P. K. Mukherjee and R. W. Simpson (1985), Virology 140, 188-191). Nucleocapsids of infecting virus particles recovered from indomethacin-treated cells were analyzed for in vitro transcriptase activity. Incorporation of [3H]UTP in mixtures containing nucleocapsids from HEp-2 cells pretreated with 10(-3) M indomethacin was inhibited approximately 80% compared to control reactions containing nucleocapsids from untreated infected cells. The level of inhibition of in vitro transcriptase activity of viral nucleocapsids from drug-treated cultures varied according to the cell line used for infection. After indomethacin removal, cells regained their ability to produce enzymatically competent viral-transcribing complexes unless they were subsequently exposed to metabolic inhibitors such as actinomycin D or alpha-amanitin. Enzymatically defective nucleocapsids from indomethacin-treated cells showed enhanced in vitro transcriptase activity in the presence of modulators of prostaglandins and cyclic nucleotides. Electrophoretic analysis of product from in vitro transcriptase reactions revealed that these defective nucleocapsids are unable to synthesize VSV messenger RNA or normal size leader RNA species but only smaller transcripts of undetermined identity.
...
PMID:Transcriptionally defective nucleocapsids of vesicular stomatitis virus from cells treated with indomethacin. 302 67

The purified RNA polymerase complex of vesicular stomatitis virus required added thiols for maximal activity, whereas polymerase activity from whole disrupted virions did not. Maximal activity of the purified polymerase complex required greater than or equal to 1 mM added dithiothreitol. The polymerase was inactivated by N-ethylmaleimide (NEM) at 0 degree C, with k2 = 528 +/- 26 M-1 min-1. Activity was recovered by addition of L protein, but not N or NS, to the NEM-inactivated complex, indicating that the NEM-sensitive group was present on the L protein. Nucleoside triphosphates protected the enzyme against inactivation by N-ethylmaleimide. ATP was most effective, with KD = 0.58 +/- 0.07 mM, a value close to the Km of ATP reported previously for initiation of RNA synthesis. dATP was nearly as effective, and GTP was slightly less effective than ATP. Non-hydrolyzable analogs of ATP protected weakly, whereas ADP and pyrimidine triphosphates gave very poor, but still measurable, protection. The ATP binding site thus identified differs from the protein kinase-associated ATP binding site identified on L protein by Sanchez et al. (Sanchez, A., De, B.P., and Banerjee, A. K. (1985) J. Gen. Virol. 66, 1025-1036) in having a substantially lower affinity for ATP. Two putative ATP binding sites were identified in the L protein amino acid sequence, but none were found in the N or NS sequences.
...
PMID:Inactivation of the RNA polymerase of vesicular stomatitis virus by N-ethylmaleimide and protection by nucleoside triphosphates. Evidence for a second ATP binding site on L protein. 303 24

Ten ribonucleic acid (RNA) tumor viruses grown in five different host cell species and three non-oncogenic viruses from three different virus groups have been examined for ribonuclease H content. Three different substrates were used to assay ribonuclease H: calf thymus [(3)H]RNA-deoxyribonucleic acid (DNA) hybrid prepared with denatured calf thymus DNA and Escherichia coli DNA-directed RNA polymerase, (3)H-polydenylic acid [(3)H-poly(A)] complexed to polydeoxythymidylic acid [poly(dT)], and (3)H-polyuridylic acid [(3)H-poly(U)] complexed to polydeoxyadenylic acid [poly(dA)]. All ten RNA tumor viruses contained ribonuclease H activity which degraded the RNA of both the calf thymus hybrid and poly(A)-poly(dT), whereas only the ribonuclease H in the Moloney strain of murine sarcoma-leukemia virus and in RD-feline leukemia virus hydrolyzed the RNA strand of poly(U)-poly(dA). No appreciable ribonuclease H activity was detected in influenza, Sendai, or vesicular stomatitis virus. The ribonuclease H and RNA-directed DNA polymerase activities in Moloney murine sarcoma-leukemia virus were inseparable by phosphocellulose chromatography or glycerol gradient centrifugation, but appeared to be partially separated by diethylaminoethyl-cellulose chromatography.
...
PMID:Ribonuclease H: a ubiquitous activity in virions of ribonucleic acid tumor viruses. 411 67

A ribonucleic acid (RNA)-dependent RNA polymerase has been demonstrated in Kern Canyon virus (KCV) particles. The RNA product of the KCV polymerase hybridizes to KCV viral RNA. The properties of this viral enzyme have been characterized and compared with those of vesicular stomatitis virus (VSV). RNA polymerases from both viruses require similar conditions of temperature, pH, and detergent and magnesium concentrations for maximal synthesis of RNA. The RNA polymerase contained in the virion of KCV was more dependent on the presence of a sulfhydryl agent than was the VSV enzyme. Under optimal conditions, the specific activity of the VSV polymerase is about twenty-five times as great as that of KCV.
...
PMID:Comparison of the ribonucleic acid polymerases of two rhabdoviruses, Kern Canyon virus and vesicular stomatitis virus. 432 91

The particle-bound RNA polymerase activity of vesicular stomatitis virus (VSV) can be demonstrated in vivo. Linear synthesis of viral RNA persists for 5 to 6 hours at 34 degrees C in infected monolayers of chick embryo cells treated with cycloheximide and actinomycin D to block synthesis of protein and cell-specific RNA. At least 55 percent of the RNA made under these conditions is complementary to virion RNA. RNA synthesis mediated by VSV polymerase activity is inhibited in cells first treated with chick-derived interferon or polyriboinosinate* polyribocytidylate, but not by mouse interferon. The RNA product of VSV polymerase activity is present throughout the cytoplasm, and its synthesis is inhibited by the interferon system, as judged by autoradiographs that show the physical distribution, in cells, of RNA produced by virion polymerase in the absence of translation-a demonstration of the transcription product of the viral genome.
...
PMID:Interferon action: inhibition of vesicular stomatitis virus RNA synthesis induced by virion-bound polymerase. 432 41

A procedure has been developed for the sequential removal and purification of the glycoprotein and membrane protein of vesicular stomatitis virus (VSV). Neither of these proteins exhibited transcriptase activity. All of the activity was recovered in the ribonucleic acid (RNA)-ribonucleoprotein complex of VSV, which also has four other minor proteins associated with it. During transcription of 41% of the RNA of a virus preparation, no dissociation of the ribonucleoprotein from the viral RNA was observed.
...
PMID:Dissociation of vesicular stomatitis virus and relation of the virion proteins to the viral transcriptase. 434 41

Transcriptase activity was dissociated from vesicular stomatitis virions by highionic-strength buffer containing Triton X-100. Considerable enzyme activity could be restored by recombining inactive sedimentable and nonsedimentable virion fractions. Reconstituted transcriptase activity was dependent on the presence of all four nucleoside triphosphates and the concentration of heat-labile molecules in both supernatant and pellet fractions. Lower NaCl concentrations removed approximately 46% of virion protein, but did not release transcriptase activity from the pellet fraction, nor could incorporation of (3)H-uridine-5'-triphosphate by complete virions be increased by adding soluble transcriptase. Evidence that the virion nucleocapsid is the transcription template was provided by finding that the pellet contained predominantly virion core nucleoprotein, ribonucleic acid, and homogeneous nucleocapsid coils when viewed by electron microscopy. Removal of envelope G and M proteins by Triton and low-salt buffer without decreasing nucleocapsid polymerase activity indicates that neither G nor M protein is necessary for transcription. Additional data are required to determine whether the minor nucleocapsid proteins L or NSl, or both, which are at least partially solubilized in high-salt buffer, are the transcriptase. Preliminary data suggest that the major N nucleoprotein, which was not solubilized by high-salt buffer, is also required for transcription. Defective T virions contained at least as much transcriptase per weight as did B virions, as determined by restoration with T supernatant fluids of transcription function to B nucleocapsid template. However, the T nucleocapsid would not serve as template for B or T transcriptase, a finding which is interpreted as evidence of T template defectiveness. The presence of defective T nucleocapsids did not interfere with B or T transcriptase function reconstituted with B template.
...
PMID:Dissociation and reconstitution of the transcriptase and template activities of vesicular stomatitis B and T virions. 434 47

The viral ribonucleic acids (RNA species) synthesized in HeLa cells infected with temperature-sensitive (ts) mutants and with the wild type of vesicular stomatitis virus at permissive (30 C) and nonpermissive (39.2 C) temperatures were compared by sucrose gradient centrifugation. Two ts mutants (ts 5 and ts 100) representing two separate complementation groups (respectively, groups I and IV), each concerned with viral RNA synthesis, were chosen. Mutant ts 5 failed to synthesize any RNA at 39.2 C. Under the same conditions, mutant ts 100 showed a low, but easily detectable, synthesis of RNA without characteristic peaks. The in vitro transcriptase activity was tested with mutants ts 5 and ts 100 at 39.2 C: normal activity, compared with wild-type virus, was detected with purified ts 100, but no activity was detected with purified ts 5. From all our data we conclude that mutant ts 5 is defective in transcription. The defect could be in the structural transcriptase enzyme or at the level of template for transcription. Results with mutant ts 100 were not so clear-cut. However, we suggest that this mutant is concerned with some aspect of transcription in vivo. In addition, our results lead us to postulate some linkage between transcription and replication.
...
PMID:Study of the transcription and the replication of vesicular stomatitis virus by using temperature-sensitive mutants. 434 55


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---