MUTAGEN SENSITIVITY IN THYMIDINE KINASE-DEFICIENT AND METHYLTRANSFERASE-DEFICIENT HUMAN LYMPHOBLASTOID-CELLS

In this study the effect of thymidine kinase deficiency on the respons es of the human lymphoblastoid cell line Raji to methyl methanesulphon ate and mitomycin C was investigated. Mutagen sensitivity was measured in terms of cell survival and mutation to hypoxanthine-guanine phosph oribosyltransferase deficiency. Thymidine kinase-deficient Raji cells showed decreased survival and increased mutant frequency relative to w ild-type cells following treatments with each of the mutagens used. It is suggested that this may be due to an imbalance in the supply of de oxyribonucleoside triphosphates to the excision repair process. The ro le of O-6-methylguanine-DNA methyltransferase in the repair of DNA dam age caused by these mutagens is also discussed.