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)

Hepatitis C virus (HCV) is a positive strand RNA virus with certain similarity to flaviviruses and pestiviruses. To examine the processing and possible assembly of HCV proteins, we constructed a recombinant vaccinia virus that expresses a full-length genomic RNA, infected chimp liver cells with the virus, and analyzed HCV-related protein products by immunofluorescent antibody staining and Western blot detection with mouse monoclonal antibodies. The putative core, envelope, and NS1 and NS3 proteins that yielded from this recombinant were 22, 32, 53 to 58, and 65 kDa in size, respectively. The NS4 protein was unexpectedly small, with an estimated molecular weight of 7 kDa, and the NS5 protein was found to be further cleaved into 52-kDa NS5a and 58-kDa NS5b proteins, the latter of which contains a hallmark of RNA replicase. A point mutation in the putative protease domain of NS3 resulted in a failure in the production of NS3, NS4, NS5a, and NS5b, but coexpression of NS3 restored the proper processing of these proteins, demonstrating that NS3, the putative viral protease, is essential for the production of these nonstructural proteins. Thus, HCV strikingly resembles pestiviruses in the size and the processing mode of the nonstructural proteins, particularly NS4 and NS5.
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PMID:Production of nonstructural proteins of hepatitis C virus requires a putative viral protease encoded by NS3. 829 Dec 45

The full-length ORFs for the hepatitis C virus recombinant RF1_2k/1b (N687) and the non-recombinant 1b strain N589 were sequenced. A single recombination point was found and the sizes of the genes (C, E1, E2, p7, NS2, NS3, NS4 and NS5) were according to the parental subtypes. The PKR-eIF2alpha phosphorylation site homology domain sequence of the E2 protein was identical to those of genotype 2 strains, while the IFN-alpha-sensitivity-determining region of the NS5A protein was identical to those of interferon-resistant 1b strains. For the parental strains, two hairpin structures, HS1 and HS2, were predicted for the plus-strand up- and downstream of the crossover site, which were not present in the recombinant strain. HS2 shared similarity with the motif1 hairpin of turnip crinkle virus RNA that binds to the RNA-dependent RNA polymerase and facilitates 3'-terminal extension during recombination. This study suggests that RF1_2k/1b has emerged by homologous recombination during minus-strand synthesis via template switching because of constraints imposed by the HS1 hairpin of the 3'-parental genome.
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PMID:Full-length open reading frame of a recombinant hepatitis C virus strain from St Petersburg: proposed mechanism for its formation. 1521 69