Characterisation of viral RNA in cells infected with the murine coronavirus JHM

The murine coronavirus JHM induces in Sac(-) cells seven major and two minor RNA species. These RNAs are polyadenylated and single stranded. Their sizes were estimated by electrophoresis in agarose gels containing methylmercury hydroxide. The mol. wts. for the major species are 6.67 x 10(6) for RNA of genome size, 3.42 x 10(6) for RNA 2, 2.76 x 10(6) for RNA 3, 1.35 x 10(6) for RNA 4, 1.19 x 10(6) for RNA 5, 0.93 x 10(6) for RNA 6 and 0.62 x 10(6) for RNA 7. The minor species have a size of 4.7 x 10(6) (RNA a) and 1.5 x 10(6) (RNA b). No essential difference in the number and proportion of each RNA species was found between total cytoplasmic RNA, polyadenylated cytoplasmic RNA and RNA extracted from pelleted polysomes, nor was any difference found during the infection cycle. The major RNA species are likely to be subgenomic mRNAs.