Tetracycline-induced mutation in cultured Chinese hamster cells

After tetracycline hydrochloride (TC) treatment for 48 h, we obtained 8-azaguanine-resistant mutants in a population of cultured Chinese hamster cells. Optimal expression of mutation was reached after about 5 days, and mutation frequency remained constant thereafter. There was a gradual increase in the yield of mutants with increasing doses of TC, and measurable yield was observed at a dose as low as 10 microgram of TC per ml. When the cells, before or after the TC treatment, were grown in presence of L-ascorbic acid (10 or 20 microgram/ml) for 48 h, there was significant decrease in the frequency of mutation induced by TC. If L-ascorbic acid were present at the same concentration during the treatment with TC, no significant influence on the induction of mutants by TC was detected.