Repair replication after U.V.-irradiation in rodent cell-lines of different sensitivity.

Abstract

SummaryRepair replication and unscheduled DNA synthesis have been demonstrated in a number of cultured tumour cell-lines of rodent origin. The amount of repair replication observed was less than that observed in HeLa cells when the same labelling procedures were used. u.v.-sensitive mutants of Yoshida cells which showed reduced D0 value and an extrapolation number of 1 showed reduced repair replication. The u.v.-sensitive mutant of L5178Y cells which differed only in its extrapolation number showed the same amount of repair replication as its more resistant mutant. The data show that (1) the amount of repair replication in rodent cells is less than that in HeLa cells and (2) that differences in amount of repair replication between two closely related cell lines are associated with changes in D0 value but not with changes in shoulder size and extrapolation number.