DNA REPAIR IN CHINESE HAMSTER CELLS OF DIFFERENT SENSITIVITIES TO ULTRA-VIOLET LIGHT

An altered Chinese hamster cell-line, V7979, derived from line V79 by irradiation with 1500 R of x-rays, is more sensitive than the parent to killing by ultra-violet (u.v.) light (V79, n = 1·6, D0 = 43 erg/mm2; V7979, n = 1·3, D0 = 30 erg/mm2). U.V. light inhibits DNA synthesis to the same extent in both cell-lines up to 11 hours after irradiation. Both cell-lines perform unscheduled synthesis, but the V7979 performs less than the V79. The amount of unscheduled synthesis is thus correlated with survival in these two closely related cell-lines. Unscheduled synthesis may therefore represent DNA repair which contributes to the recovery of u.v.-damaged cells. © 1969 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.