Characterization of the RNA Mycovirus Infecting Allomyces arbuscula

Summary The mycovirus infecting Allomyces arbuscula has been fractionated into two particle classes designated A and B. Particles A have a buoyant density of 1.385 g/cm3, in CsCl, a sedimentation coefficient of 75S and contain one major and two minor polypeptides with molecular weights of 34000, 31000 and 28000, respectively. Particles B band at 1.335 g/cm3, sediment with a value of 67S and, in addition to the three polypeptides as in particles A, they contain seven extra polypeptides, six of which are of lower molecular weights. Both particles A and B contain double-stranded RNA which was resolved by electrophoresis on polyacrylamide gels into three components with molecular weights of 1.4 (major), 2.5 and 1.1 × 106 (minor). Both particles also contain single-stranded RNA. Particles A contain 27% RNA whereas particles B only contain 14%. Evidence is presented that particles A and B belong to the same type of virus and represent two different replicative stages.