A genetic locus for inducibility of C-type in BALB-c cells: the effect of a nonlinked regulatory gene on detection of virus after chemical activation.

Previous studies have shown that chemicals can transiently activate endogenous C-type viruses from embryo cells of the BALB/c mouse strain, but not from cells of another mouse strain, NIH Swiss. The number of genetic loci for inducibility of endogenous virus in BALB/c cells was investigated with cell lines derived from appropriate, F(1), F(2)-hybrid, and backcross generation embryos of these strains. A single genetic locus responsible for inducibility of virus in BALB/c cells was detected, and tentatively designated Ind. A second locus, previously described in studies of mouse-cell susceptibility to exogenous virus infection, Fv-1, was found to be genetically nonlinked to Ind. This regulatory gene plays an important role in determining whether the induced viruses of BALB/c cells can persist after chemical activation.