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)

The effects of 3'-amino-3'-deoxy- and 3'-azido-3'-deoxyribonucleoside-5'-triphosphates on the RNA synthesis catalyzed by influenza virus A RNA polymerase were studied. All nucleotide analogues tested decreased the RNA synthesis twofold at the inhibitor: substrate ratio about 1:5 (in moles). The hypothetic mechanism of inhibitors action based on the incorporation of inhibitors into the 3'-termini of the RNA chains and subsequent blocking of the RNA chains elongation is proposed. The nucleotide analogues under investigation were several times more effective as compared with the ribavirine 5'-triphosphate, a well-known inhibitor of influenza A virus reproduction.
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PMID:[Inhibition of influenza virus A RNA-polymerase activity by various 3'-amino-3'-deoxy- and 3'-azido-3'-deoxyribonucleoside-5'-triphosphates]. 357 17

An in vitro system for the synthesis of influenza viral RNA was developed using isolated nuclei prepared from influenza virus-infected HeLa cells. In this system, two species of positive-sense RNA, i.e., mRNA and cRNA (complementary RNA to vRNA), were found to be synthesized when analyzed by RNA-RNA hybridization using a minus-strand RNA probe and high resolution gel electrophoresis. The in vitro RNA synthesis required Mg2+, GTP, CTP, UTP, a high concentration of ATP, and an ATP regenerating system. Neither actinomycin D nor alpha-amanitin, potent inhibitors for cellular DNA-dependent RNA polymerases, inhibited the RNA synthesis. Addition of ApG or capped RNA, well-known primers for virion-associated RNA polymerase, markedly enhanced the extent of RNA synthesis. The maximum activity was observed with nuclei isolated from cells at 5 h after infection. This system is useful for the purification and characterization of factors involved in the transcription of these two species positive-sense RNA.
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PMID:In vitro synthesis of influenza viral RNA: characterization of an isolated nuclear system that supports transcription of influenza viral RNA. 361 Oct 43

Activity of RNA polymerase was studied in original non-pathogenic for mice viruses of influenza A and B (A/seal/Massachusetts 1/80, A/USSR 05/81, A/Philippines 2/82 and B/Singapore 227/79) and of their pathogenic derivatives. All the non-pathogenic viruses studied exhibited the low rate of transcriptase activity. Pathogenic derivatives of these strains exhibited higher activity of RNA polymerase, which was 1.5-3-fold higher as compared with the original strain. During passage of influenza viruses A and B in mice organism selection of the population appears to occur, which had the highest transcriptase activity.
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PMID:[Comparative study of the RNA-polymerase activity of non-pathogenic and pathogenic influenza viruses A and B]. 366 Jul 48

Oligodeoxynucleotides covalently linked to an acridine derivative were targeted to part of the 3'-terminal sequence which is common to the eight RNAs of type A influenza viruses. The cytopathic effect of the virus on MDCK cells in culture was strongly decreased by a heptanucleotide covalently attached to the acridine ring. Control experiments using other oligonucleotide sequences showed that the effect was specific for the complementary sequence of the 3'-terminal region of the viral RNAs. The RNA transcriptase reaction of a type A virus was also selectively inhibited in vitro by the heptanucleotide-acridine conjugate. A type B influenza virus was used as a control. The common sequence at the 3' end of its eight viral RNAs is different from that of type A viruses. Three mismatches were expected with the heptanucleotide which was fully complementary to type A viral RNAs. This heptanucleotide had no effect on the cytopathic effect of a type B influenza virus. These results demonstrate that viral RNAs are specific targets for the oligonucleotide-acridine conjugate that inhibits the cytopathic effect of type A influenza viruses.
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PMID:Selective inhibition of the cytopathic effect of type A influenza viruses by oligodeoxynucleotides covalently linked to an intercalating agent. 369 85

RNA polymerase activities in parental strains of influenza A and B viruses nonpathogenic for mice and their pathogenic variants have been studied. The parental strains are A/seal/Massachusetts 1/80, A/USSR 05/81, A/Philippines 2/82, B/Singapore 222/79. The RNA polymerase activity has been also studied in recombinant strains obtained by crossing various parental strains, one of which is pathogenic for mice (AR/PR 8/34), and having different degrees of pathogenicity. The nonpathogenic viruses had low transcriptase activity. RNA polymerase activity in pathogenic variants is shown to be 1.5-3 times higher than that in the parental strains. All the recombinants, whatever their pathogenicity, had approximately the same transcriptase activities which were 1.5-2 times higher than those registered in parental nonpathogenic strains.
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PMID:[Activity of virion RNA-polymerase in influenza A and B virus variants with different pathogenicities for mice]. 380 28

An RNA polymerase-viral RNA complex was purified from influenza A/PR/8 virions by combination of cesium trifluoroacetate centrifugation and phosphocellulose column chromatography. Surface proteins were removed from the detergent-treated virions by the centrifugation. Starting from the M protein-free ribonucleoprotein (RNP) fraction, an RNA polymerase-RNA complex lacking NP protein was isolated by repeated chromatography on phosphocellulose columns. The isolated RNA polymerase-RNA complex, which is composed of PB1, PB2, PA and vRNA, cleaved capped poly(A) endonucleolytically at 10-12 nucleotides from the 5' end and incorporated GMP into the 3' end of the resulting capped fragments. In the presence of all four ribonucleotide triphosphate substrates, the cleaved fragments were elongated to polynucleotides in the absence of exogenous vRNA. The RNA synthesis was primed not only by capped polynucleotides but also dinucleotide ApG. These results indicate that the purified RNA polymerase-RNA complex is as active in viral mRNAs synthesis as native RNP and that NP protein is not required for the catalytic function.
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PMID:Purification and enzymatic properties of an RNA polymerase-RNA complex from influenza virus. 384 Jun 35

These studies examine the effect of ribavirin triphosphate (RTP) on two replicative functions associated with influenza virus nucleocapsids, primer generation and its subsequent elongation. To study primer generation influenza virus cores were added to beta-globin mRNA in the presence of only [32P]GTP. To examine elongation, ATP and CTP were added to the reaction mixture to permit limited elongation, and products from both reactions were separated on polyacrylamide gels and quantified. Under these conditions, the 50% inhibitory concentration of RTP for primer generation was 3.0 mM, and the 50% inhibitory concentration for elongation was 0.6 mM. RNA polymerase activity associated with cores isolated from clinical strains of influenza A and B viruses reacted as did the laboratory strain of influenza virus and was equally susceptible to inhibition by RTP.
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PMID:Effect of ribavirin triphosphate on primer generation and elongation during influenza virus transcription in vitro. 398 7

During the generation of primer for transcription initiation by endonucleolytic cleavage of capped RNA, the influenza virus-associated RNA-dependent RNA polymerase recognizes three signals of capped RNA, i.e., cap-1 structure at 5' termini, RNA sequences at the cleavage sites, and distance between these two signals (Plotch, S.J., Bouloy, M., & Krug, R.M. (1979) Proc. Natl. Acad. Sci. U.S. 76, 1618-1622; Kawakami, K., Mizumoto, K., & Ishihama, A. (1983) Nucl. Acids Res. 11, 3637-3649). The free cap-1 structure, i.e., m7GpppNm not associated with polynucleotides, stimulates the RNA synthesis as well, irrespective of the presence or absence of dinucleotide primers. Since the stimulation by m7GpppNm and ApG is additive and the free cap-1 structure is not incorporated into 5' termini of product RNA, we propose that the cap-1 structure stimulates the RNA polymerase by allosteric modulation rather than by priming the transcription initiation.
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PMID:Activation of influenza virus-associated RNA polymerase by cap-1 structure (m7GpppNm). 400 72

An investigation was made of inhibition of transcriptase activity of influenza viruses in vitro by binding of antibody to the surface of the virion. Eight monoclonal antibodies which were directed against at least four non-overlapping antigenic regions of the haemagglutinin protein of A/Aichi/68 virus were tested for inhibitory effect. One of the antibodies directed against the B antigenic site, 22/1, inhibited transcriptase activity, while the other seven antibodies did not. Antibody from a hyperimmune rabbit serum to A/Udorn/72 (H3N2) virions inhibited the transcriptase activity of A/Udorn/72 and A/Aichi/68 (H3N2) viruses but not that of A/WSN/33 (H1N1). The antibody did not cause irreversible inactivation of the transcriptase since full activity was recovered by isolating ribonucleoprotein (RNP) cores from the inhibited virions using NP-40 treatment and subsequent centrifugation in a caesium sulphate density gradient. The antibody did not inhibit transcriptase activity of isolated RNP cores. The virion transcriptase activity was not inhibited by addition of the antiserum after the detergent treatment which is necessary for the activation of the transcriptase activity in vitro. These results suggest that the antibody blocks the activation process of the transcriptase by detergent treatment.
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PMID:Inhibition of transcriptase activity of influenza A virus in vitro by anti-haemagglutinin antibodies. 406 Aug 49

Influenza virus mRNA synthesis is primed by a capped oligonucleotide which is cleaved off from a cellular mRNA by a viral protein. The dinucleotide A3'p5'G can be used as a primer for the viral RNA polymerase mediated RNA synthesis in a cell-free system. Analogues of A3'p5'G have therefore been synthesized using the phosphotriester approach, and their priming ability for the influenza virus mRNA synthesis has been determined. An absence of the 2'-hydroxyl function in the guanosine residue in the dinucleotide, as in A3'p5'dG, drastically decreased its priming ability. Similarly, an alteration of the 3'----5' phosphate linkage to a 2'----5' phosphodiester linkage affected the priming ability quite severely. However a dinucleotide, with the 2'-hydroxyl function omitted in the adenosine moiety, as in dA3'p5'G, could still stimulate the mRNA synthesis. None of the modified dinucleotides inhibited A3'p5'G or globin mRNA primed influenza mRNA synthesis.
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PMID:Synthesis of adenylyl-(3'----5')-guanosine and some analogues as probes to explore the molecular mechanism of stimulation of influenza virus RNA polymerase. 408 42


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