A Satellite Double-stranded RNA in a Virus from Gaeumannomyces graminis

Abstract

The double-stranded (ds)RNA components of 2 serologically related viruses (019/6-A and 38-4-A), obtained from G. graminis, were compared. 019/6-A virus has 3 RNA components, ds1 and ds2; 38-4-A virus has 3 RNA components, ds1, ds2 and ds3. T1 oligonucleotide fingerprint analysis and saturation hybridization experiments indicated that 019/6-A ds1 and 38-4-A ds1 were similar; 019/6-A ds2 and 38-4-A ds2 were .apprx. 50% homologous. 38-4-A ds3 had little homology with ds1 or ds2 of either virus. The single-stranded (ss)RNA transcripts of 38-4-A virus ds1, ds2 and ds3 each directed the synthesis in vitro of a single polypeptide with MW 62,000, 55,000 and 52,000, respectively. Peptide mapping showed that these 3 polypeptides were unrelated in sequence and that ds2 encoded the virus capsid polypeptide. The ds3 is probably not required for the replication of 38-4-A virus and may be regarded as a satellite RNA.