A new method for the isolation of undegraded FMDV-specific RNA from infected BHK cells.

Fractionation of Foot-and-Mouth disease virus infected cells by currently described procedures, leads to the appearance of variable amounts of heterogeneous single-stranded RNA fragments. A new method based upon the fractionation of cultured cells at extremely low temperatures has been developed to minimize the degradation of the viral RNAs by cellular nucleases. It was shown that the viral RNAs obtained by this procedure were almost non-degraded, and similar to those found in other picornavirus infected cells. More than 90 per cent of the polysomal RNAs were found as genome-size molecules, presumably being messenger RNA (mRNA). It was also found that the mRNA analyzed on sucrose gradients sedimented slightly ahead of the 35S genomic RNA. However, no differences were found when the analysis was performed on polyacrylamide gels.