Replication of Viral Rna, Vi. Nucleotide Composition of the Replicative Form of Tobacco Mosaic Virus Rna and of Its Component Strands

Multiplication of plant viruses containing single-stranded RNA' such as TYMV2 and TMV3 "4is accompanied by the formation of a virus-specific double-stranded RNA designated as the replicative form.Similar findings have been made in the case of animal viruses5' 6 and bacteriophages.7-10We have previously reported on the properties of the partially purified replicative form of TMV-RNA.4Because of the small amounts available, the base composition of this material could not be determined at that time.We have now purified the P32-labeled replicative form by a modified procedure and obtained analyses both of the duplex and of its com- ponent strands.