Genetic control of oncogenesis by murine sarcoma virus Moloney pseudotype. II. A dominant epistatic susceptibility gene.

We have shown in the preceding paper that AKR mice are highly resistant to M-MSV tumor development, and that resistance is transmitted as a dominant character. In the present studies the tumor-response pattern of F1 hybrids between resistant AKR and susceptible strains (C57Bl/6, BALB/c and B10BR) following injection with Moloney mouse sarcoma virus (M-MSV) resembles that of the non-AKR parent. Segregation is observed in first backcross (Bc1) and F2 mice, and the segregation ratios up to Bc3 mice fit a one-gene model. The data of triple cross hybrids suggests that this dominant susceptibility gene inhibits the phenotypic expression of M-MSV tumor resistance in some susceptible Fv1bb strains as well as in their hybrids with AKR. Neither Fv-1 nor H-2 exerts any significant influence on this complex system.