title: RNA polymerase activity catalyzed by a potyvirus-encoded RNA-dependent RNA polymerase.
abstract: We have expressed the putative RNA-dependent RNA polymerase encoded by the potyvirus tobacco vein mottling virus (TVMV) in Escherichia coli as a glutathione S-transferase fusion protein. As prepared, the fusion protein possessed the poly(U) polymerase activity that is a hallmark of other picornavirus-encoded polymerases. In addition, this protein was able to utilize full-length TVMV RNA as a template for RNA synthesis. A fusion protein containing a mutation in the highly conserved GDD motif of the polymerase (GDD-->ADD) possessed 7% of the activity of the wild type. Our results confirm that the presumed polymerase encoded by TVMV is in fact an RNA-dependent RNA polymerase and that the GDD motif so widely seen in viral polymerases has an important function in the TVMV protein.
authors.affiliation: Department of Agronomy, University of Kentucky, Lexington 40546-0091, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Hong
authors.forename: A G
authors.initials: AG
authors.lastname: Hunt
mesh_terms: D012321:DNA-Directed RNA Polymerases; D011061:Poly A / Q000378:metabolism; D017800:Potyvirus / Q000201:enzymology*; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D011061:Poly A; D012324:RNA-Dependent RNA Polymerase; C061396:nuclear inclusion protein b, mosaic viruses; D012321:DNA-Directed RNA Polymerases