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 nucleotide sequence of the genomic RNA1, 7342 nucleotides (nt) of grapevine fanleaf virus strain F13 (GFLV-F13) has been determined from cDNA clones. The complete sequence contained only one long open reading frame (ORF) of 6852 nucleotides extending from nucleotide 243 to 7101. The putative polyprotein encoded by this ORF is 2284 amino acids in length with an Mr of 253K. The location of genome-linked protein and comparison of the primary structure of the 253K polyprotein to that of other closely related viral proteins of the picronavirus-like family allows the proposal of a scheme for the genetic organization of GFLV-F13 RNA1. The primary structure of the polyprotein includes a putative RNA-dependent RNA polymerase of 92K and a cysteine protease of 25K. This protease shares not only major structural homologies, particularly in the substrate-binding pocket, with the trypsin-like serine proteases of other picorna-like viruses, but also their specificity in terms of cleavage. The large region of Mr 133K upstream of the VPg was found to contain at least two domains, one of which could be easily aligned with the NTP-binding sequence pattern and another which may have the characteristics of a protease cofactor. Thus, the 253K protein possesses the same general genetic organization as the corresponding protein of other picorna-like viruses.
J Gen Virol 1991 Oct
PMID:Complete nucleotide sequence and genetic organization of grapevine fanleaf nepovirus RNA1. 165 53

cDNA clones representing the ssRNA genome of the NY-RPV isolate of barley yellow dwarf luteovirus (BYDV) were sequenced and 5600 nucleotides of the genome were determined. The deduced genome organization has limited similarity to that of another BYDV isolate, Vic-PAV, but is identical to that of beet western yellows (BWYV) and potato leafroll (PLRV) luteoviruses. NY-RPV has six major positive-sense open reading frames (ORFs) and, by comparison with RNA-dependent RNA polymerase and nucleic acid helicase consensus sequence motifs, it is postulated that NY-RPV ORF2 and ORF3 encode the viral replicase, which is expressed by a translational frameshift mechanism. The region of the NY-RPV genome containing the 22K coat protein ORF, the apparently associated internal apparent VPg ORF and the ORF immediately 3'-proximal (ORF6) to the coat protein ORF are organized as reported for other luteoviruses. Evidence is presented showing that ORF6 is expressed by readthrough of the coat protein gene termination codon, and that this protein is associated with the intact virus as a 65K protein. Although NY-RPV infects graminaceous rather than dicotyledonous plants, the taxonomic relationships between BYDV isolates and other luteoviruses deduced from the genome organization and sequence data strongly suggest that NY-RPV is distinct from the PAV-like isolates of BYDV and is more closely related to BWYV and PLRV.
J Gen Virol 1991 Oct
PMID:Nucleotide sequence analysis and genomic organization of the NY-RPV isolate of barley yellow dwarf virus. 184 Jun 12

The sequence of 6746 nucleotides representing the 3'-proximal half of the beet yellows closterovirus (BYV) genome was determined. In the direction 5' to 3', the sequence was composed of eight open reading frames (ORFs) potentially encoding proteins of 6.4K (ORF2), 65K (ORF3), 64K (ORF4), 24K (ORF5), 22K (ORF6), 20K (ORF7) and 21K (ORF8). An incomplete ORF, ORF1, encoded the C-terminal part of a putative RNA-dependent RNA polymerase, most closely related to polymerases of tricornaviruses; the putative product of ORF3, 65K, was found to be a homologue of the hsp70 family of cell heat-shock proteins. ORF2 potentially encoded a small hydrophobic 6.4K protein, apparently homologous to small hydrophobic proteins of potex- and carlaviruses. ORF6 encoded the viral coat protein, as indicated by its deduced Mr and amino acid composition. The products of ORFs 4, 5, 7 and 8 showed no significant similarities with protein sequences in the database and there are therefore no justifiable speculations concerning their possible functions. BYV RNA contains a 3'-terminal non-coding region of 181 nucleotides, with two stem-loop structures potentially folded within the 86 nucleotide sequence at the extreme 3' end. Analysis of the primary and secondary structure of this region together with the absence of aminoacylation and adenylylation in vitro showed that the BYV genome is devoid of a tRNA-like structure at its 3' end.
J Gen Virol 1991 Jan
PMID:Nucleotide sequence of the 3'-terminal half of beet yellows closterovirus RNA genome: unique arrangement of eight virus genes. 199 61

The 8534 nucleotide sequence of the genome of the carlavirus, potato virus M (PVM), has been determined. The sequence contains six large open reading frames (ORFs) and non-coding regions consisting of 75 nucleotides at the 5' end, 70 nucleotides followed by a poly(A) tail at the 3' end and 38 and 21 nucleotides between three large blocks of coding sequences. The ORF beginning at the first initiation codon at nucleotide 76 encodes a polypeptide of 223K which, according to its primary sequence analysis, seems to be a virus RNA replicase. The next coding block consists of three ORFs encoding polypeptides of 25K, 12K and 7K. The third block consists of two ORFs encoding polypeptides of 34K (PVM coat protein) and 11K. The 11K polypeptide contains a pattern resembling the consensus for a metal-binding nucleic acid-binding 'finger'.
J Gen Virol 1991 Jan
PMID:The genome organization of potato virus M RNA. 199 70

The putative viral transcriptase p90 in infectious bursal disease virus (IBDV) was shown to form an enzyme-guanylate intermediate which is indicative of guanylyl-transferase activity. The p90-nucleotide bond is most likely to be a phosphodiester linkage, as it resisted treatment with HCl and NH2OH but was sensitive to NaOH. This is in contrast to phosphoamide bonds formed by reovirus cores. Methyltransferase activity was also demonstrated in IBDV, and is closely associated with transcription, suggesting that p90 may be a multifunctional enzyme.
J Gen Virol 1990 Apr
PMID:Demonstration of enzyme activities required for cap structure formation in infectious bursal disease virus, a member of the birnavirus group. 215 6

An RNA-dependent RNA polymerase associated with particles of maize rough dwarf virus, a Fijivirus, was characterized using two in vitro assays differing in their energy regeneration systems. Optimum reaction rates occurred at pH 8.0 to 8.5 at 20 degrees C. The presence of virus and Mn2+ or Mg2+ was essential for enzyme activity; Mn2+ stimulated more incorporation events than Mg2+, at optimum concentrations of 2 to 4 mM and 4 mM, respectively. Incorporation was not affected by alpha-amanitin, actinomycin D or rifampicin. The products synthesized in vitro were single-stranded RNAs which hybridized specifically with the double-stranded genomic RNAs of five other reoviruses. The in vitro transcripts were also used to detect maize rough dwarf virus RNA in plants and in vector insects.
J Gen Virol 1990 Mar
PMID:In vitro transcription of the double-stranded RNA genome of maize rough dwarf virus (Reoviridae). 231 68

Ten of 12 Chandipura virus tdCE mutants, which exhibit temperature-dependent restriction of growth in chick embryo (CE) cells but not in BS-C-1 cells, showed deficient transcriptase activity in vitro at 39 degrees C relative to wild-type virus. A gradation in transcriptional activity at 39 degrees C in vitro was observed. Reversion of the tdCE phenotype to unrestricted growth in CE cells at 39 degrees C was accompanied by partial restoration of normal transcriptase activity at 39 degrees C, suggesting that reversion was mediated by either extragenic or intragenic suppression. Viral protein synthesis was reduced or absent in CE cells at 39 degrees C indicating that transcription was also defective in vivo under these conditions. Induction of heat-shock proteins in CE cells at 39 degrees C occurred normally in tdCE mutant-infected cells and RNA methylation in vitro was unaffected.
J Gen Virol 1986 May
PMID:In vitro transcriptase deficiency of temperature-dependent host range mutants of Chandipura virus. 242 18

Even when neutralized by saturating amounts of monoclonal IgG directed against the haemagglutinin, influenza virus attaches to cells with kinetics similar to those of infectious virus. It then enters those cells and is uncoated; its RNA becomes localized within the nucleus and its lipid envelope and associated proteins remain in the cytoplasm. In this report we show that despite the apparent normality of these early stages of virus-cell interaction, neutralized virus underwent no detectable primary transcription. In contrast, there was only a slight inhibition of transcription by neutralized virus in vitro which was insufficient to account for the loss in infectivity, despite using mRNA to measure the production of capped oligonucleotides or to prime the elongation step. To test whether the absence of primary transcription in vivo resulted from non-accessibility of the genome rather than an effect on the transcriptase complex itself, we examined the susceptibility to RNase of virion RNA after inoculation of cells with neutralized virus. Data clearly show that, unlike RNA of infectious virus, RNA of neutralized virus did not become sensitive to RNase and we conclude that neutralization of influenza virus by IgG results in failure of virus to undergo a secondary uncoating process which is necessary for the activity of the virion transcriptase complex. Finally we show that by treatment of virions in vitro with detergent it is possible to produce a core structure which is stable and has some of the properties expected of a structure resulting from primary uncoating.
J Gen Virol 1989 Aug
PMID:IgG-neutralized influenza virus undergoes primary, but not secondary uncoating in vivo. 276 31

The two variants of influenza A/Victoria/35/72 (H3N2) virus resistant simultaneously to remantadine, deitiforin, adapromine and amantadine were obtained while passaging the virus in presence of remantadine or deitiforin. Both variants differed from the parental strain in optimal pH for hemolysis, transcriptase activity and in amino acid sequence of M2 protein. Maximal hemolytic activity of the parental strain is registered at pH 5.2, for the variants cultured in the presence of remantadine or deitiforin at pH 5.5 and 5.8, respectively. In contrast to NH4OH, remantadine and deitiforin do not exert inhibition of virus-induced hemolysis. Transcriptase activity of resistant variants is about 50% higher as compared with parental strain (enzyme source--whole virus particles or RNP). The M2 protein of the remantadine variant has 2 amino acid substitutions: 31 (Ser----Asn) and 59 (Met----Leu); the deitiforin variant has 3 substitutions: 14 (Met----Leu), 30 (Ala----Val) and 59 (Met----Leu). The phenotypic resistance of the virus seems to be determined by the mutations in the hydrophobic protein region (30,31); the other substitutions (14,59) may modify conformational structure and functional activity of the viral proteins.
Mol Gen Mikrobiol Virusol 1989 Jun
PMID:[The change in functional activity and primary structure of the M2 protein in variants of the influenza virus resistant to remantadine and deitiforin: common and individual differences from the original strain]. 281

The 26S mRNA and most of the nsP4 encoding regions of the eastern equine encephalomyelitis (EEE) viral genome have been cloned. Excluding the poly(A) tail, the 26S mRNA region was determined to be 4139 nucleotides long and to share the same general organization as that of other alphaviruses. A highly conserved region of 19 nucleotides, the putative transcriptase recognition site for 26S mRNA synthesis, was present at the 26S/42S junction region of the 42S genomic RNA. Translation of the 26S mRNA began at the first AUG (positions 59 to 61) initiation codon and continued with an open reading frame that coded for a polyprotein of 1258 amino acids ending at a UAA ochre termination codon (positions 3776 to 3778). All four putative posttranslational cleavage sites used to generate the capsid, E3, E2, 6K and E1 proteins were conserved. Transmembrane domains present in the EEE virus structural polyprotein have been identified and their functions discussed. Pairwise comparison of the deduced amino acid sequences of the polyproteins of five alphaviruses (EEE, Venezuelan equine encephalitis, Sindbis, Semliki Forest and Ross River viruses) revealed EEE virus to be more closely related to VEE virus than to the other three viruses.
J Gen Virol 1987 Aug
PMID:Nucleotide sequence of the genome region encoding the 26S mRNA of eastern equine encephalomyelitis virus and the deduced amino acid sequence of the viral structural proteins. 288 48


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