FIG 8.

RNA packaging phenotype of the most commonly arising S2b revertant. (A) Plaques of S2b-rev1 at 39°C compared with those of the original S2b mutant and wild-type virus. Plaque titrations were carried out on L2 cells; monolayers were stained with neutral red at 72 h postinfection and were photographed 18 h later. (B) Northern blot of RNA isolated from normalized amounts of immunopurified wild-type, S2b, or S2b-rev1 virions. MHV RNA was detected with a probe specific for the 3′ end of the genome.