title: A closely related group of RNA-dependent RNA polymerases from double-stranded RNA viruses.
abstract: Probably one of the first proteinaceous enzymes was an RNA-dependent RNA polymerase (RDRP). Although there are several conserved motifs present in the RDRPs of most positive and double-stranded RNA (dsRNA) viruses, the RDRPs of the dsRNA viruses show no detectable sequence similarity outside the conserved motifs. There is now, however, a group of dsRNA viruses of lower eucaryotes whose RDRPs are detectably similar. The origin of this sequence similarity appears to be common descent from one or more noninfectious viruses of a progenitor cell, an origin that predates the differentiation of protozoans and fungi. The cause of this preservation of sequence appears to be constraints placed on the RDRP by the life-style of these viruses--the maintenance of a stable, persistent, noninfectious state.
authors.affiliation: Department of Biological Sciences, State University of New York, Buffalo 14260.
authors.forename: J A
authors.initials: JA
authors.lastname: Bruenn
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D008969:Molecular Sequence Data; D012328:RNA Viruses / Q000201:enzymology* / Q000235:genetics; D012330:RNA, Double-Stranded / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism*
chemical_list: D012330:RNA, Double-Stranded; D012324:RNA-Dependent RNA Polymerase