Effects of antisense oligodeoxynucleotide hybridization on in vitro translation of potato virus Y RNA.

Potato virus Y (PVY), a potyvirus, has an RNA genome containing 9704 nucleotides of which 185 belong to the 5' nontranslated region (NTR). Contrary to most eukaryotic mRNAs that have a cap structure, the potyvirus RNA has a genome-linked protein (VPg). In order to understand the mechanisms of PVY RNA translation initiation, hybrid-arrest translation was used to localize sequences involved in binding of proteins and/or ribosomes. The 5' NTR was fused to the beta-glucuronidase (GUS) reporter gene. Six antisense oligodeoxynucleotides were used for hybridization, and the efficiency of the in vitro translation of the hybridized mRNA was modified to different levels depending upon the position of the oligodeoxynucleotide used. The highest inhibition was obtained with an oligodeoxynucleotide hybridized to the 5' end. In addition, translation of GUS mRNA containing the PVY 5' NTR was greatly enhanced when this mRNA was capped. These results differ from those obtained with the tobacco etch virus (TEV) and three picornaviruses, but are similar to those obtained with capped mRNA.