In vitro Transcription of Double-Stranded RNA by Reovirus-Associated RNA Polymerase

Viruses which contain a double-stranded, seg-mented RNA genome are known to infect both plants and animals. These include cytoplasmic polyhedrosis virus of insects (Kalmakoff, Lewan-dowski, and Black, 1969), wound tumor and rice dwarf viruses (Miura, Kimura, and Suzuki, 1966), which replicate in both their insect vectors and plant hosts, African horsesickness virus, blue-tongue virus of sheep (Verwoerd, Louw, and Oellermann, 1970), and the ubiquitous reoviruses of vertebrates (for reviews see Shatkin, 1968, and Gauntt and Graham, 1969). It is of interest to examine how these viruses initiate replication since double-stranded RNAs function poorly, if at all, as messengers (Singer, Jones, and Nirenberg, 1963; Miura and Muto, 1965). Although cellular polym-erases capable of transcribing double-stranded RI~IA efficiently have not been observed (Shatkin, 1965), there is associated with the purified virion of reoviruses an RNA polymerase which transcribes the double-stranded genome segments in vitr