Effects of hydroxyurea consistent with the inhibition of repair synthesis in ultraviolet irradiated HeLa cells.

Many studies on DNA repair using established in vitro cell cultures employ conditions of low serum, nutrient deprivation, and blockade with hydroxyurea (HU) to reduce the background levels of DNA replication. There are some reports in the literature which indicate that HU inhibits DNA repair. In the present study the effects of HU on strand breaks and repair synthesis in UV irradiated Hela cells were investigated using a combined strand break and UDS assay. In conditions of low serum and arginine deprivation, HU produced effects consistent with the inhibition of the repair synthesis step in excision repair. Although the conditions used in this study are severe the results suggest that HU may have qualitatively similar effects in other studies which employ its use to detect repair synthesis.