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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The in vitro characteristics of human rotavirus transcription have been examined. The virus has an associated RNA polymerase activity which was activated after a heat shock treatment. The enzyme required the presence of the four ribonucleoside triphosphates and a divalent cation (Mg2+), and it required an optimum pH of 8.5. The polymerase was activated by monovalent salts and inhibited by Na PPi. The addition of actinomycin D, alpha-amanitin, or rifampin did not inhibit the polymerase activity. After thermal shock of the virus, at least eight different RNA species were synthesized which may correspond to independent transcripts. Transcription also requires a hydrolyzable form of ATP. Analogs such as beta,gamma-imido ATP or beta,gamma-methylene ATP were inhibitory, whereas others, such as the beta-gamma-imido or methylene analogs of CTP, UTP, or GTP, were not inhibitory. This suggests that ATP is related to reactions other than polymerization, probably to initiation or elongation of RNA molecules, as has been described for vesicular stomatitis virus or vaccinia virus.
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PMID:In vitro transcription catalyzed by heat-treated human rotavirus. 627 Mar 65

The ability of the compound 2',3'-dideoxycytidine 5'-triphosphate (ddCTP) to serve as an inhibitor of viral RNA synthesis was examined using an in vitro system that supports vesicular stomatitis virus (VSV) protein synthesis, transcription and replication. Viral RNA synthesis was inhibited by 87 and 98% of control, respectively, in reactions containing 1 mM- and 10 mM-ddCTP in place of CTP. VSV RNA replication and transcription were inhibited equally by ddCTP. At a concentration of 1 mM-ddCTP, there was no inhibitory effect on viral protein synthesis; at 10 mM-ddCTP, total protein synthesis was inhibited by 30% as compared to control reactions. The presence of ddCTP had no effect on the size or relative molar amounts of each protein synthesized as analysed by electrophoresis on polyacrylamide gels. This is the first report describing a compound that will inhibit VSV RNA synthesis in vitro without compromising the concurrent synthesis and modification of proteins.
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PMID:Inhibition of vesicular stomatitis virus RNA synthesis by 2',3'-dideoxycytidine 5'-triphosphate. 629 55

Interferons induce a number of different proteins which mediate the antiproliferative, antiviral, and immunomodulatory functions of interferons. Interferon-induced Mx proteins, which confer resistance to influenza, vesicular stomatitis, and measles viruses, contain consensus GTPase sequence elements. Insect cell-produced purified murine Mx1 and human MxA proteins were found to hydrolyze GTP with Km = 65 microM (Vmax, 7.1 min-1) and 62 microM (Vmax, 3.1 min-1), respectively. The GTPase activity of Mx1 and MxA proteins was strictly dependent on Mg2+ ions. Murine Mx1 protein was inactivated at 10 degrees C lower temperatures than MxA protein. As analyzed, by filter binding assay, Mx1 protein (at 1 microM) showed a relatively high affinity for GDP (Kd = 1.0 x 10(-7) M) and approximately 340-fold lower affinity for guanosine 5'-3-O-(thio)triphosphate (GTP gamma S) (Kd = 3.4 x 10(-5) M). The Kd values for MxA protein were 2.0 x 10(-7) M for GDP and 5.9 x 10(-6) M for GTP gamma S, showing approximately a 30-fold affinity difference. ATP, UTP, or CTP did not inhibit the Mx protein-dependent GTPase activity, suggesting that Mx1 and MxA proteins are highly specific for guanosine nucleotides. In conclusion recombinant nuclear murine Mx1 and cytoplasmic human MxA proteins show clear differences in their enzymatic activities and nucleotide binding characteristics. How these differences influence their cellular functions and antiviral potential is presently not known.
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PMID:Enzymatic characterization of interferon-induced antiviral GTPases murine Mx1 and human MxA proteins. 750 89

The phosphoprotein (P) of vesicular stomatitis virus (VSV) is a subunit of the RNA polymerase (L) that transcribes the negative strand genome RNA into mRNAs both in vitro and in vivo. We have previously shown that the P protein of VSV, expressed in E. coli, is biologically inactive unless phosphorylated at specific serine residues by cellular casein kinase II (CKII). In the present study we present evidence that the P protein, in addition to being phosphorylated, binds covalently to GTP only when it is phosphorylated. Competition experiments show that ATP, ADP, GTP, and GDP can compete for the binding site(s) of GTP but not AMP, GMP, CTP, or UTP. Interestingly, once GTP is bound to P protein it cannot be displaced by unlabeled GTP. The GTP binding site has been mapped within the domain where the phosphorylation of P protein by CKII occurs. Finally, we show that phosphorylation negative P mutants P3A (P60A, P62A, P64A), P3E (P60E, P62E, P64E), and P3R (P60R, P62R, P64R) failed to bind to GTP, indicating that phosphorylation of P is indeed essential for binding to GTP. Although the precise role of binding of GTP to P is unclear, it appears that phosphorylation of P may initiate a structural change within the P protein allowing GTP to bind, thus manifesting biological function to the transcription factor.
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PMID:Novel binding of GTP to the phosphoprotein (P) of vesicular stomatitis virus. 1217 45

The RNA synthesis machinery of non-segmented negative-sense RNA viruses comprises a ribonucleoprotein complex of the genomic RNA coated by a nucleocapsid protein (N) and associated with polymerase. Work with vesicular stomatitis virus (VSV), a prototype, supports a model of RNA synthesis whereby N is displaced from the template to allow the catalytic subunit of the polymerase, the large protein (L) to gain access to the RNA. Consistent with that model, purified L can copy synthetic RNA that contains requisite promoter sequences. Full processivity of L requires its phosphoprotein cofactor and the template-associated N. Here we demonstrate the importance of the 2' position of the RNA template and the substrate nucleotide triphosphates during initiation and elongation by L. The VSV polymerase can initiate on both DNA and RNA and can incorporate dNTPs. During elongation, the polymerase is sensitive to 2' modifications, although dNTPs can be incorporated, and mixed DNA-RNA templates can function. Modifications to the 2' position of the NTP, including 2',3'-ddCTP, arabinose-CTP, and 2'-O-methyl-CTP, inhibit polymerase, whereas 2'-amino-CTP is incorporated. The inhibitory effects of the NTPs were more pronounced on authentic N-RNA with the exception of dGTP, which is incorporated. This work underscores the sensitivity of the VSV polymerase to nucleotide modifications during initiation and elongation and highlights the importance of the 2'-hydroxyl of both template and substrate NTP. Moreover, this study demonstrates a critical role of the template-associated N protein in the architecture of the RNA-dependent RNA polymerase domain of L.
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PMID:Sensitivity of the polymerase of vesicular stomatitis virus to 2' substitutions in the template and nucleotide triphosphate during initiation and elongation. 2452 87


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