DNA repair in ultraviolet-irradiated HeLa cells is disrupted by aphidicolin. The inhibition of repair need not imply the absence of repair synthesis.

Aphidicolin, a potent and specific inhibitor of eukaryotic DNA polymerase alpha, has been reported to inhibit repair DNA synthesis in ultraviolet-irradiated, normal human fibroblasts but not in HeLa cells. By the use of assays for repair other than the measurement of repair synthesis, it is shown here that repair in HeLa cells is in fact susceptible to aphidicolin. Severe inhibition of DNA repair, with failure of individual repair events to be completed, and a smaller number of lesions removed, can occur even though repair synthesis continues.