X-ray dose response for mutation to fructose utilisation in cultured diploid human fibroblasts

Abstract

THE majority of studies relating to somatic cell mutation in cultured mammalian cells have been performed with established (heteronuclear) mammalian cells². There are important karyotypic and metabolic differences, however, between cultured heteronuclear cells and mammalian cells in vivo and mutation in cultured diploid (homonuclear) cells may be more relevant to the in vivo situation. Mutation, in the broadest sense of the term¹, has been studied in cultured diploid cells^2–9 and there is evidence, from the work of Albertini and DeMars² with 8-azaguanine resistant (Ag^r) variants of diploid human fibroblasts, that it may be possible to quantify radiation-induced mutation in diploid mammalian cells. Here we report that the utilisation of fructose, in place of glucose, as the major carbon and energy source, was used as a phenotypic character for mutation studies with a culture of diploid human fibroblasts. Although not yet fully understood, the fructose-utilisation mutation system does circumvent some of the problems of mutation expression time associated with the selection of Ag^r variants of cultured mammalian cells.