%0 Journal Article %A Fellers, John %A Wan, Jinrong %A Hong, Yiling %A Collins, Glenn B. %A Hunt, Arthur G. %T In vitro interactions between a potyvirus-encoded, genome-linked protein and RNA-dependent RNA polymerase %D 1998 %J Journal of General Virology, %V 79 %N 8 %P 2043-2049 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-79-8-2043 %I Microbiology Society, %X 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 coincubated 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 Nlb with an altered ‘GDDߣ motif. Our studies thus provide two lines of evidence indicative of in vitro interactions between the TVMV VPg and Nlb proteins. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-79-8-2043