using the distinct and unvarying mobility of the rf viral p12 protein on sds-page as a marker , we show that the rf-derived ecotropic murine leukemia virus ( mulv ) is expressed to the exclusion of the balb/c-derived ecotropic mulv in f1 hybrid mice of the balb/c x rf cross , and that variant viruses expressed in f1 radiation-induced lymphomatous tissue display the pattern of variation characteristic of the rf , and not of the balb/c , strain .
C0042736
viral
C0042776
viruses