Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 7/26/1996
Publication Date: N/A
Technical Abstract: Potyviruses express their RNA genomes through the production of polyproteins that are processed in host cells with the aid of three virus encoded proteases. To analyze two of the protease functions of SMV G2, we cleaved a full-length cDNA clone of SMV G2 BamHI and SalI and transcribed the cDNAs in vitro. The transcripts produced from the BamHI-cut cDNA template included ll of the Pl and helper component protease (HC-Pro) genes. The in vitro ranslation products observed were approximately 85 kDa, which corresponded to the size of the unprocessed polypeptide. The SalI-cut cDNA template included all of the Pl, HC-Pro and P3 genes and the 5'-end of the cylindrical inclusion (CI) gene. Two polypeptides were observed in the in vitro translation. The larger, approximately 85 kDa, probably corresponded to fusion of the Pl-HC-Pro polypeptides. The smaller, approximately 50 kDa, was consistent with the size of the P3-CI cleavage product from the C-terminus of the truncated polyprotein. These in vitro translation data show the 35 kDa of Pl protein was not cleaved from the HC-Pro protein in the rabbit reticulocyte lysate in vitro translation system as has been reported for other potyviruses.