A search for an intermediate involving a complement during synchronous synthesis by a purified RNA replicase.

Abstract

If purified Q[beta]-replicase is presented with fragments of Q[beta]-RNA, the reaction is slow (10% of normal), abbreviated (ceases within 30 min), and biologically abnormal. The product is small, biologically inactive, and much of it is complexed in a heat-denaturable RNase-resistant structure. In contrast, when activated by intact templates, Q[beta]-replicase produces virtually unlimited amounts of complete and biologically competent replicas of Q[beta]-RNA. Further, no heat-sensitive RNaseresistant material can be detected. Finally, neither the base composition nor annealability to "plus" strands revealed any compelling evidence for an initial appearance of complete complementary strands. All the data on the early products are explainable in terms of partial copies of a template possessing a beginning sequence rich in adenine and another sequence complementary to it further on in the chain. For the Q[beta]-virus, a double-stranded replicative intermediate mechanism of RNA replication has not been established.