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:2.7.7.48 (transcriptase)
9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of several adamantane derivatives on the activity of virion-associated RNA-dependent RNA polymerase of fowl plague virus (FPV) and influenza B virus was studied in vitro. Some of the derivatives inhibited the activity of the polymerase by 60 per cent. A correlation was established between the previously demonstrated capacity of these inhibitors to suppress orthomyxovirus reproduction in vivo and their ability to reduce the activity of virion-associated RNA-dependent RNA polymerase in vitro.
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PMID:Effect of adamantane derivatives on the activity of orthomyxovirus RNA-dependent RNA polymerase. 0 25

The activities, the temperature and pH optima of in vitro functioning and stability upon heating of virion transcriptase of 10 human influenza virus A strains differing in reactogenicity and isolated in different epidemiological situations, and of fowl plague virus (FVP) were compared. As compared with virion transcriptase of human influenza virus strains studied, that of FPV had a higher pH optimum, was capable of functioning in vitro at a higher temperature and was more stable on heating. Freshly isolated and vaccine influenza virus strains on the one hand and strains isolated at the peak and in the end of an epidemic did not differ in the virion transcriptase properties. The virion transcriptase of a strain isolated from a local influenza outbreak was much less active than transcriptase of a highly epiedmic strain.
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PMID:Comparative study of virion transcriptase of some influenza virus strains. 2 10

The activity of RNA-dependent RNA polymerase of several influenza viruses is stimulated by guanosine. Depending upon the virus strain used, the stimulation of initial reaction rate is up to 10-fold. 5'-GMP, 3',5'-cyclic GMP, and 5'-GDP show lesser stimulation effects. No other nucleosides of 5'-NMPs stimulate, but the dinucleoside monophosphates GpG and GpC show large stimulations. We present evidence that the stimulation represents preferential initiation of genome complementary RNA chains with guanosine: (i) [3-H] guanosine is incorporated specifically at the 5'terminus of RNA in polymerase reaction mixes in vitro. (ii) This incorporation reaction has several properties similar to those of the virion polymerase elongation reaction. (iii) RNA made in the stimulated reaction behaves as complementary RNA in annealing kinetic studies, as does RNA labeled with [3-H]guanosine.
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PMID:Influenza virion RNA-dependent RNA polymerase: stimulation by guanosine and related compounds. 16 15

We have recently demonstrated that globin mRNAs are effective primers for influenza viral RNA transcription in vitro catalyzed by the virion transcriptase [Bouloy, M., Plotch, S. J. & Krug, R. M. (1978) Proc. Natl. Acad. Sci. USA 75, 4886-4890]. Here, we present direct evidence that the 5'-terminal methylated cap of the globin mRNAs is transferred to viral complementary RNA (cRNA) during transcription. Chemical (beta-elimination) or enzymatic removal of the cap of globin mRNAs eliminated essentially all their priming activity. Much of this activity could be restored by recapping the beta-eliminated globin mRNAs with the vaccinia virus guanylyl and methyl transferases. Globin mRNAs containing (32)P label only in the cap (m(7)G(32)pppm(6)A(m)-) were prepared by recapping beta-eliminated globin mRNAs with the vaccinia virus enzymes, [alpha-(32)P]GTP, and unlabeled S-adenosylmethionine. By using this labeled globin mRNA as primer and unlabeled nucleoside triphosphates as precursors, the viral cRNA segments that were synthesized were shown to contain a (32)P-labeled 5'-terminal cap structure. Gel electrophoretic analysis indicated that the globin mRNA-primed cRNA segments were 10-15 nucleotides longer at their 5' end than ApG-primed cRNA segments, which initiate exactly at the 3' end of the virion RNA templates. This suggests that, in addition to the cap, about 10-15 other nucleotides are also transferred from the globin mRNA to viral cRNA. A mechanism for the priming of influenza viral cRNA synthesis by globin mRNA is proposed.
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PMID:Transfer of 5'-terminal cap of globin mRNA to influenza viral complementary RNA during transcription in vitro. 28 3

Present epidemic influenza is uncontrolled by immuno- or chemoprophylaxis. Mutants of varying antigenic composition arise with relatively high frequency in nature and are able to circumvent herd, or induced, immunity. Also, drug-resistant viruses can be selected in vitro and this resistance can be exchanged to other viruses by gene reassortment. Combined immuno- and chemoprophylaxis may provide a more effective approach to the ultimate control of the disease. Most antiviral compounds have been selected by random screening in the laboratory. Application of more specific enzyme assays such as the virion-associated RNA transcriptase assays may produce other compounds with a defined mode of action - semi-rational chemotherapy. RNA and polypeptide sequence studies are in progress elsewhere to define transcription and translation initiation sites or virus adsorption sites. Such knowledge could lead to a new generation of antiviral compounds. Specific delivery of virus inhibitory compounds is an interesting problem. Liposomes are lipid spheres, and these have been used for the delivery of antiviral compounds.
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PMID:Approaches towards rational antiviral chemotherapy. 46 Dec 75

Recombinants of human influenza type A viruses, A/Krasnodar/101/1959 (H2N2) or A/Habarovsk/15/1976 (H3N2), and fowl plague virus (FPV), strain Weybridge (Hav1Neq1) were obtained. The genome of the recombinant obtained by recombination of influenza A/Habarovsk/15/1976 virus and FPV contained the genes 4 (HA) and 6 (NA) derived from the influenza A/Habarovsk virus and all the other genes [1, 2, 3, 5 (NP), 7 (M), 8 (NS)] from FPV. The genome of the recombinant of A/Krasnodar/101/1959 virus and FPV contained the genes 2, 4 (HA) and 6 (NA) derived from influenza A/Krasnodar virus and all the other genes [1, 3, 5, (NP), 7 (M), 8 (NS)] from FPV. The recombinants, like FPV, gave high virus yields in chick embryos and could multiply at high temperatures (40 and 42 degrees C), but, like human influenza viruses, were non-pathogenic for chickens and did not replicate in chick embryo fibroblast culture, but did replicate in a human conjunctiva cell line, clone 1-5C-4. The virion transcriptase of the recombinants, in a number of properties determined in vitro, was similar to FPV transcriptase but not to the human influenza virus enzyme.
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PMID:Investigation of recombinants of human influenza and fowl plague viruses. 47 41

The state of the secondary structure of RNA and proteins comprising nucleoids (cores) and RNP of influenza virus was evaluated comparatively. The identity of RNA conformation in these particles and differences from free RNA conformation due to less marked secondary structure were found. Core proteins were predominantly represented by the beta-framework, and RNP as an alpha-helix. The specific transcriptase activity of the core is significantly lower than RNP activity of influenza virus.
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PMID:[Characteristics of the structural organization and transcriptase activity of the influenza virus nucleoid]. 50 99

Reovirus mRNA's containing a 5'-terminal methylated cap structure (m(7)GpppG(m)) were shown to be effective primers for influenza viral RNA transcription in vitro catalyzed by the influenza virion transcriptase. Priming activity required the presence of methyl groups in the cap since reovirus mRNA's with 5'-terminal GpppG were inactive as primers. Both the cap and internal nucleotides were physically transferred from radiolabeled reovirus mRNA to influenza viral complementary RNA (cRNA) during transcription in vitro. By using reovirus mRNA's with methyl-(3)H-labeled caps as primers, we showed that the influenza viral cRNA synthesized in the presence of unlabeled nucleoside triphosphates contained [methyl-(3)H]m(7)GpppG(m), identical to that found in the reovirus mRNA primer. To demonstrate transfer of internal residues, reovirus mRNA's synthesized in the presence of all four alpha-(32)P-labeled ribonucleoside triphosphates were used as primers. The resulting influenza viral cRNA was (32)P-labeled. Diethyl-aminoethyl-Sephadex chromatography of the RNase T2 digest of this cRNA demonstrated (32)P radiolabel in both internal residues (charge -2) and the cap (charge -4.6). Approximately 25 internal nucleotides along with the cap of reovirus mRNA were transferred to each chain of influenza viral cRNA. Gel electrophoretic analysis indicated that the segments of influenza viral cRNA primed by reovirus mRNA were approximately the same size as those primed by a different mRNA, globin mRNA, strongly suggesting that the influenza virion transcriptase complex transfers approximately the same number of nucleotides plus the cap from different mRNA primers to the 5' end of influenza viral RNA transcripts.
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PMID:Cap and internal nucleotides of reovirus mRNA primers are incorporated into influenza viral complementary RNA during transcription in vitro. 51 5

RNA 1 (see end of Summary) of a cold-adapted and temperature-sensitive (ts) influenza virus mutant A/Ann Arbor/6/60 has a different mobility from RNA 1 of wild-type (wt) A/Ann Arbor/6/60 when subjected to electrophoresis through acrylamide/agarose gels in the absence of denaturing agents. Detection of this lesion in RNA 1 of the mutant virus was dependent on the temperature of the gel during electrophoresis. Because RNA 1 is believed to code for a protein involved in virus-specific RNA synthesis we compared phenotypes of virion transcriptases in the wt and mutant viruses. The enzyme of the mutant virus was found to be about 40% less active at 40 degrees C than the enzyme of the wt virus when related to their activities at 31 degrees C. Two cold-adapted ts recombinants which derive their RNA 1 from the mutant A/Ann Arbor/6/60 have virion transcriptases with a phenotype similar to that of their mutant parent. Three different cold-adapted ts recombinants, however, which also derive their RNA 1 from the mutant A/Ann Arbor/6/60, have virion transcriptases with a phenotype similar to that of wt virus. We conclude, therefore, that the conditional-lethal ts property of A/Ann Arbor/6/60 mutant and its recombinants is independent of the phenotypic marker observed for the A/Ann Arbor/6/60 mutant virion transcriptase, and that the lesion in RNA 1 of the mutant may also be unrelated to the observed difference between virion transcriptases of the mutant and wt A/Ann Arbor/6/60 viruses. The phenotypes of the virion transcriptases in recombinants did, however, correlate with the derivation of their RNA 2. This suggests that the increased temperature-sensitivity of virion transcriptase of the A/Ann Arbor/6/60 mutant is caused by either (1) a lesion (not necessarily conditionally lethal) that occurred in its RNA 2 during the course of cold-adaptation, or (2) a lesion in another gene whose product is a component of the virion transcriptase complex, but which lesion is only expressed phenotypically when there is a synergistic interaction in the transcriptase complex with the product of A/Ann Arbor/6/60 rna 2.
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PMID:Comparative studies of wild-type and cold-mutant (temperature-sensitive) influenza viruses: independent segregation of temperature-sensitivity of virus replication from temperature-sensitivity of virion transcriptase activity during recombination of mutant A/Ann Arbor/6/60 with wild-type H3N2 strains. 52 98

Structural and virus-induced infected cell polypeptides of several strains of influenza B virus were examined by high resolution polyacrylamide gel electrophoresis and shown to be directly analogous to those of the influenza A viruses. Eight structural polypeptides, P1, P2, P3, HA1, HA2, NA, NP and M were observed in purified virus and at least two additional polypeptides, HA and NS could be detected in infected MDCK cells. The three P proteins plus NP were shown to be associated with RNA-dependent RNA polymerase activity and HA, HA1, HA2 and NA were shown to be glycosylated. Like the influenza A viruses, migrational differences of some of the infected cell polypeptides could be observed between different B strains. Investigation of a time course of virus replication failed to show any temporal control of protein synthesis in the infected cell.
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PMID:The structural and infected cell polypeptides of influenza B virus. 54 75


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