Mutagenicity and DNA repair of glycidamide-induced adducts in mammalian cells

A significant induction of mutations by GA was detected in the hprt locus of wild-type cells but not in BER deficient cells. Cells deficient in HR or BER were three or five times, respectively, more sensitive to GA in terms of growth inhibition than were wild-type cells. The results obtained on the rate of incisions in BER and NER suggest that lesions induced by GA are repaired by short patch BER rather than long patch BER or NER. Furthermore, a large proportion of the GA-induced lesions gave rise to strand breaks that are repaired by a mechanism not involving PARP. It is suggested that these strand breaks, which might be the results from alkylation of the backbone phosphate, are misrepaired by HR during replication thereby leading to a clastogenic rather than a mutagenic pathway. The type of lesion responsible for the mutagenic effect of GA cannot be concluded from the results presented in this study.