Chromosomal assignment of two murine genes controlling susceptibility to spleen focus formation by Rauscher leukemia virus.

Two murine genes affecting susceptibility to spleen focus formation by RLV were assigned to chromosomes. The gene Rv-2, which controls susceptibility to spleen focus formation, was assigned to chromosome 9, and closely linked to the Fv-2 gene, by using the two congenic strains B10.C(47N)/Sn and B6.C-H-7b/By. These congenic strains, which were previously shown to carry the BALB/cJ allele for susceptibility to FLV on chromosome 9, were also susceptible to RLV, as determined by number of foci on the spleens of infected mice. A second gene which contributes to the susceptibility to spleen focus formation by RLV was assigned to the X chromosome because hemizygous male offspring of crosses between resistant-strain females and susceptible-strain males (C57BL/6J X CBA/Lac) showed significantly lower numbers of foci/spleen than the female littermates and than the offsprings, males and females, of the reciprocal cross (CBA/Lac X C57BL/6J). We suggest this gene be called Rv-3.