Replication of Viral Rna. Iv. Properties of Rna Synthetase and Enzymatic Synthesis of Ms2 Phage Rna.

Evidence has been presented' for the accumulation of a double-stranded replicative form of MS2 RNA in vivo, following infection of Escherichia coli with MS2 phage, and for the identity of this material with the double-stranded RNA which is labeled in vitro with radioactive carbon2 on incubation of CL4-labeled ribonucleoside triphosphates with RNA synthetase.3 The present paper is concerned with a new method for the partial purification of RNA synthetase, the properties of theenzyme, and the mechanism of synthesis of MS2 RNA. The results suggest that RNA synthetase is purified as a holoenzyme in association with its natural template, the double-stranded replicative form of MS2 RNA, and show that on incubation with labeled nucleoside triphosphates most of the radioactivity introduced into double-stranded material is present as parental type, "plus" MS2 RNA strands. The enzymatic replication of viral RNA is thus conclusively demonstrated for the first time.