Further physicochemical characterization of Nodamura virus. Evidence that the divided genome occurs in a single component

Animal Virus Research Institute, Pirbright, Surrey Nodamura virus, a small non-enveloped RNA virus, contains two species of RNA sedimenting at 22S (RNA-1) and 15S (RNA-2), a single major polypeptide of mol. wt. 40 x 10 3 and two minor polypeptides, of mol. wt. 38 and 43 x 10 3 . Evidence is presented that the two RNA species are in the same particle. Although extraction of the virus with SDS-phenol yields the two species of RNA as separate entities, gentle treatment of the virus with guanidine and low concentrations of SDS releases the RNA as a 27S component which contains both RNA-1 and RNA-2 together with a trace of protein. It seems likely that the two RNA species replicate separately because double stranded molecules corresponding to the single stranded RNA-1 and RNA-2 molecules were present in BHK cells infected with the virus. Received 20 May 1977; accepted 5 August 1977.