Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have constructed a full-length cDNA clone of the virulent T48 strain of Ross River virus, a member of the alphavirus genus. Infectious RNA can be transcribed from this clone using SP6 or T7 RNA polymerase. The rescued virus has properties indistinguishable from those of the T48 strain of Ross River virus. We have used this clone, together with a full-length cDNA clone of Sindbis virus, to construct chimeric plasmids in which the 5' and the 3' nontranslated regions of the Sindbis and Ross River genomes were exchanged. The nontranslated regions of the two viral genomes differ in both size and sequence although they maintain specific conserved sequence elements. Virus was recovered from all four chimeras. Chimeras containing heterologous 3' nontranslated regions had replicative efficiencies equal to those of the parents. In contrast, the chimeras containing heterologous 5' nontranslated regions were defective in RNA synthesis and virus production, and the severity of the defect was dependent upon the host. Replication of a virus containing a heterologous 5' nontranslated region may be inefficient due to the formation of defective protein-RNA complexes, whereas, the presumptive complexes formed between host or virus proteins and the 3' nontranslated region to promote RNA synthesis appear to function normally in the chimeras.
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PMID:Infectious RNA transcripts from Ross River virus cDNA clones and the construction and characterization of defined chimeras with Sindbis virus. 167 12

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.
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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