In vitro interactions between a potyvirus-encoded, genome-linked protein and RNA-dependent RNA polymerase

John Fellers, Jinrong Wan, Yiling Hong, Glenn B. Collins, Arthur G. Hunt

Research output: Contribution to journalArticlepeer-review

62 Scopus citations

Abstract

Recent studies have shown that potyvirus VPg/proteinases and RNA-dependent RNA polymerases are capable of protein-protein interactions in yeast cells. We have extended these studies in vitro. We found that tobacco vein mottling virus (TVMV) VPg is retained on glutathione-Sepharose matrices if co-incubated with a glutathione S-transferase (GST)-Nlb fusion protein, but not with GST, which is suggestive of a direct physical interaction between these two proteins. However, a mutation in the VPg (Y1860S) that eliminates virus infectivity and the interaction in yeast cells had little effect on the in vitro interaction. We also found that the TVMV VPg and Nla proteins are capable of stimulating the polymerase activity of the Nlb protein. Since this stimulatory activity is retained when the proteinase domain of the Nla is removed, we conclude that the VPg is the moiety responsible for the stimulation of polymerase activity. As with the interaction revealed by co-purification, the Y1860S mutation had little or no effect on the stimulation of polymerase activity. Moreover, the VPg was able to stimulate a mutant Nib with an altered 'GDD' motif. Our studies thus provide two lines of evidence indicative of in vitro interactions between the TVMV VPg and Nlb proteins.

Original languageEnglish
Pages (from-to)2043-2049
Number of pages7
JournalJournal of General Virology
Volume79
Issue number8
DOIs
StatePublished - Aug 1998

ASJC Scopus subject areas

  • Virology

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