SEQUENCE COMPLEMENTARITY OF SONCHUS YELLOW NET VIRUS-RNA WITH RNA ISOLATED FROM THE POLYSOMES OF INFECTED TOBACCO

Polyribosomal RNA from tobacco infected with sonchus yellow net virus (SYNV) contained sequences which hybridized to 125I-labeled SYNV RNA and which were complementary to 80 to 100% of the viral RNA genome. The poly(A)-containing RNA from polyribosomes was complementary to over 90% of the viral genome but the polyribosomal RNA lacking poly(A) hybridized to approximately 40-60% of the genome. The kinetics of hybridization of all three fractions are best explained by the presence of a single abundance class of viral-complementary RNA. However, titration hybridization of poly(A)+ RNA to an excess of SYNV RNA suggested that viral-complementary sequences which contain poly(A) may vary in concentration over a factor of about fivefold. About 1.5 to 4.6% of the fraction containing poly(A), 0.02 to 0.06% of the fraction lacking poly(A) and 0.04 to 0.18% of the total polyribosomal RNA was complementary to viral RNA as estimated from the kinetics of hybridization. The viral complementary RNA(vcRNA) was heterogeneous in size with a modal sedimentation coefficient of 12 S and a profile in sucrose density gradients similar to the polyadenylated polyribosomal RNA. © 1979.