Increased persistence of induced mutants of Chinese hamster cells by 12-O-tetradecanoylphorbol-13-acetate.

Hypoxanthine phosphoribosyltransferase deficient mutants of Chinese hamster ovary cells induced by ethyl methanesulfonate usually do not maintain their phenotype during growth in non-selective medium immediately following the induction. This phenomenon, called poor "persistence" of the induced mutation, is in most cases unrelated to growth rate but results from establishment of contact with wild type cells (Bradley, W. E. C. Exp. Cell Res., 129: 251, 1980). We report here that 12-O-tetradecanoylphorbol-13-acetate, a strong tumor promoter, increases the persistence of these mutants.