FIG. 4.

Nondenaturing Northern analyses of cell-free virion RNAs from MLV. (A and B) Representative nondenaturing Northern blots of cell-free virion RNAs. RNAs were either not heated (25°C) or heated for 10 min at the indicated temperatures prior to electrophoresis; riboprobes containing hygro sequences were used in these analyses. (C) Thermostability of the virion RNA dimer from wild type or mutant MLV particles. The proportions of dimeric and monomeric RNAs in the Northern analyses were quantified by a PhosphoImager. Data from three independent experiments are shown as means ± standard deviations.