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 double-stranded RNA genome of giardiavirus (GLV) has only two large open reading frame (ORFs). The 100-kDa capsid polypeptide (p100) is encoded by ORF1, whereas the only other viral polypeptide, the 190-kDa GLV RNA-dependent RNA polymerase (p190), is synthesized as an ORF1-ORF2 fusion protein by a (-1) ribosomal frameshifting. Edman degradation revealed that p100 was N-terminally blocked except for 2 to 5% of it that showed free N terminus starting from amino acid residue 33 of ORF1. Studies using antiserum targeted against amino acid residues 6 to 27 indicated that this region (NT) is absent from viral p100 and p190, while pulse-labelling experiments showed that NT is present in nascent p100 synthesized in GLV-infected Giardia lamblia but removed subsequently. In contrast, this region was retained in the two viral proteins synthesized in vitro, and it was not removed upon prolonged incubation or inclusion of microsomal fraction in the in vitro translation reaction mixtures. These results suggest that endoplasmic reticulum is not involved in the protein processing and that the precursors of p100 and p190 are incapable of cleaving themselves or each other. This specific cleavage was reproduced when lysates from GLV-infected G. lamblia were added, but not those from uninfected cells. The cleavage activity was relatively insensitive to phenylmethylsulfonyl fluoride, but it was inhibitable by leupeptin or E-64, two known specific inhibitors of cysteine protease. The possible origin of this processing activity is discussed.
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PMID:Maturation of giardiavirus capsid protein involves posttranslational proteolytic processing by a cysteine protease. 770 5

The complete nucleotide sequences of genomic segments S1 to S6 from Dendrolimus punctatus cypovirus 1 (DpCPV-1) have been determined. Each segment of S1 to S6 possess a single open reading frame. Conserved motifs 5' (AGUAA) and 3'(GUUAGCC) were found at the ends of each segment. Comparison of the proteins of DpCPV with those of other members in the family Reoviridae lead us to suggest that S1, S3, S4 and S6 encode the viral structural protein VP1, VP2, VP3 and VP4, respectively. S5 encoded viral non-structural protein p100 and S2 encodes an RNA-dependent RNA polymerase (RdRp). Motif analysis shows that VP3 is similar to the methyltransferase of Methanosarcina mazei Goe1, VP4 has motifs for leucine zipper and ATP/GTP-binding sites, and p100 is remarkably similar to foot-and-mouth disease virus 2A protease (FMDV 2Apro). Phylogenetic analysis of RdRps from nine viruses of the family Reoviridae indicates that DpCPV is a type 1 cypovirus, more related to Bombyx mori cypovirus (BmCPV) than to other cypovirus species. DpCPV is more related to Rice ragged stunt virus (RRSV) than to other members of different genera of the family Reoviridae, which seems to confirm the previous hypothesis that plant reoviruses originated from insect reoviruses.
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PMID:Genomic sequence analyses of segments 1 to 6 of Dendrolimus punctatus cytoplasmic polyhedrosis virus. 1282 65