Hypoxanthine-guanine phosphoribosyltransferase deficiency: chemical agents selective for mutant or normal cultured fibroblasts in mixed and heterozygote cultures.

Cultured fibroblasts established from skin biopsies from patients with the Lesch-Nyhan syndrome are deficient in hypoxanthine-guanine phosphoribosyl-transferase (EC 2.4.2.8) activity. This deficiency makes possible the use of chemicals that select either for or against deficient variants in cultured fibroblasts. Two-way selection has been achieved by the use of 6-thioguanine, which selects for the deficient mutant, and azaserine, which selects to some extent for the normal allele in mixed cultures, as well as in cultures from heterozygotes. Theoretical considerations predict that the phenomenon of metabolic cooperation would tend to reinforce the former and to weaken the latter type of selection, and this is in accordance with the experimental findings.