Translation of potato virus S RNA in vitro: evidence of protein processing.

RNA from potato virus S (PVS), a member of the carlavirus group, was translated in vitro in rabbit reticulocyte lysate. Time-course experiments revealed the largest product of Mr 190 kD, decreasing in intensity after 60-min incubations, correlating with the accumulation of a 150-kD peptide. This apparent processing could be blocked by the addition of the amino-acid analogues p-fluorophenylalanine and L-canavanine for phenylalanine and arginine, respectively. L-canavanine also appeared to specifically reduce the quantity of PVS (34 kD) coat protein, concomitant with the synthesis of a 36-kD peptide. Sucrose gradient-fractionated genomic RNA directed the synthesis of predominantly 190-kD peptides that appeared not to be processed in the absence of small molecular weight (subgenomic) RNA products.