The use of guanidine-HCl for the isolation of both RNA and protein from RNA tumour viruses.

The RNA components of two C-type RNA viruses, avian myeloblastosis virus and Friend leukaemia virus, have been isolated by treatment of the viruses with 6 M-guanidine-HCl and precipitation with ethanol. The virus proteins were recovered by lyophilization of the guanidine-HCl-ethanol supernatant after thorough dialysis against 0.5 mM-dithiothreitol. This simple method yielded RNA of similar quality to the phenol and sodium dodecyl sulphate (SDS) extraction methods, and the same amount of 60-70S RNA, although a fraction of the smaller (4S) species remained in the protein fraction. The sedimentation patterns of heat-denatured RNA extracted by either method were similar. Electrophoretic analyses of the extracted proteins in polyacrylamide gel gradients containing SDS gave patterns that were very similar to those obtained by direct analysis of SDS disrupted viruses.