IN VITRO TRANSLATION OF TOMATO BUSHY STUNT VIRUS RNA AND CARNATION RINGSPOT VIRUS RNA

Viral RNA isolated from purified tomato bushy stunt virus (TBSV) and carnation ringspot virus (CRSV) was translated in the wheat-germ and reticulocyte systems and synthesized polypeptides were analyzed by polyacrylamide gel electrophoresis. TBSV RNA directed synthesis of intense products with molecular weights of 38, 35 and 32 x 10(\u273) Mr in the wheat-germ system. The 38 and 32 x 10(\u273) Mr polypeptides were often less intense on gels when synthesized in the reticulocyte system than in the wheat germ system. An 87 x 10(\u27-3) Mr product produced in the wheat-germ system was absent the reticulocyte translations. CRSV RNA directed synthesis of intense products with molecular weights of 38, 34, 32 and 26 x 10(\u273) Mr in the wheat-germ system. As was the case for TBSV RNA products the 38 and 32 x 10(\u273) Mr products were less intense in the reticulocyte system. CRSV RNA also sometimes directed synthesis of 50 and 26 x 10(\u273) Mr products. The 38 x 10(\u273) polypeptides produced in vitro by CRSV RNA and TBSV RNA were identified as coat proteins of these respective viruses by co-migration with in vivo labeled coat protein on polyacrylamide gels and by immunoprecipitation. No post-translational cleavage products were detected in kinetic experiments. Translation products of both TBSV and CRSV RNA fractionated in sucrose gradients revealed that the coat protein is directed with greater efficiency from less than full length viral RNA of TBSV. The 35 x 10(\u273) Mr product is produced in relatively greater amounts from full length RNA. RNA 1 of CRSV directs synthesis of predominately a 34 x 10(\u273) Mr product whereas RNA 2 appears to direct synthesis of the 50, 38, 34, and 26 x 10(\u273) Mr products. Polyribosomes isolated from healthy and TBSV infected Nicotiana clevelandii were translated in the wheat-germ system. The polyribosomes from infected plants synthesized two viral-specific products (38 and 35 x 10(\u273) Mr) that comigrated with the 38 and 35 x 10(\u273) Mr products directed by TBSV RNA in vitro