Induction of 6-Thioguanine Resistance in Synthronized Human Fibroblast Cells Treated with Methyl Methanesulfonate, N-Acetoxy-2-Acethylaminofluorene and N-Methyl-N'-Nitro-N-Nitrosoguanidine

摘要

Chemical induction of 6-thioguanine resistance was studied in synchronized human fibroblast cells. Cells initially grown in a medium lacking arginine and glutamine for 24 h ceased DNA synthesis and failed to enter the S phase. After introduction of complete medium, the cells progressed to the S phase after 16 h. DNA synthesis peaked 20 h after removal of nutrient stress and declined. Mutations were induced in S-phase cells by methyl methanesulfonate (MMS), N-acetoxy-2-acetylaminofluorene (NA-AAF) and N-methyl-N nitro-N-nitrosoguanidine (MNNG). Chemical treatments resulted in an increase in the absolute number of mutant colonies and in a dose-dependent mutation frequency.