Host cell reactivation of irradiated adenovirus in UV-sensitive Chinese hamster ovary cell mutants

In this study we have utilized the ability of rodent cells to replicate viral DNA following semi-permissive infection by human adenovirus (Ad) to examine the host cell reactivation (HCR) of radiation-damaged Ad in several UV-sensitive Chinese hamster ovary (CHO) cell mutants. A significant reduction in HCR of viral DNA synthesis for UV-irradiated Ad was detected in a series of UV-sensitive mutants from complementation groups 1-6 derived from parental CHO-AA8 cells. HCR for UV-irradiated Ad in these CHO mutants varied from 18.8 to 48.0% of that in parental AA8 cells. However, a significant reduction in HCR of viral DNA synthesis for UV-irradiated Ad could not be detected in series of UV-sensitive PV mutants from complementation groups 1, 5, 9 and 10 derived from parental CHO-K1 cells, which harbour relatively small DNA repair deficiencies. We also report a reduced HCR for gamma-irradiated Ad in UV-sensitive CHO cell mutants from groups 1 and 4 derived from parental CHO-AA8 cells. This HCR technique for DNA synthesis of Ad can be employed to measure the DNA repair capacity of both human and rodent cells and extended to examine the repair of DNA damaged by a variety of different physical and chemical agents.