[Sedimentation characteristics of virion RNA of Machupo virus reproducing in the presence of actinomycin D].

Actinomycin D treatment (0.005-05 g/ml) of Vero and BHK-21 cells infected with Machupo virus suppressed the synthesis of ribosomal RNAs but did not affect the production of infectious Machupo virus. Virion RNAs contained 3 high molecular weight RNA species: 28-31 S, 22-24 S and 18 S. In the presence of actinomycin D [3H]-uridine incorporated only in 30-31 S and 22-24 S RNA species. The data are supported by previous results which show that Machupo virus genome contains two RNA species: "large" (30-31 S) and "small" (22-24 S).