Role of the AKR Gene Locus AKv-1 in Susceptibility to Chemical Induction of Thy mie Lymphomas1

Various strains of mice demonstrate widely differing susceptibility to chemical induction of thymic lymphomas, in both timing and incidence. In AKR mice tumors appear very early and at high incidence after a single dose of W-methyl-jV-nitrosourea, while in other strains they appear later and at lower incidences. In an attempt to determine the potential role of AKR ecotropic murine leukemia virus loci in this process, congenie mice of NFS/N background, into which the highly productive ecotropic murine leukemia virus loci AKv-l or AKv-2 has been transferred, were challenged with A'-methyl-/V-nitrosourea. Although they had a lower incidence of thymic lymphomas than did the parental donor AKR, the NS.AKv-1 mice had a tumor incidence twice that of NFS/N or NS.AKv2. However, no difference in timing was noted, and these three strains demonstrated tumor appearance much later than that of AKR/N. It is suggested that the presence of the AKv-l loci, or a gene of the closely associated genomic region, increases the number of target cells that are susceptible to A'-methyl-A'-nitrosourea.