Processing of clustered DNA damage site in

Shikazono, Naoya; Pearson, P.*; Thacker, J.*; O'Neill, P.*

To gain insights on the processing of the DHT + 8-oxoG cluster in vivo, several potential intermediates after removal of base lesions were assessed for their transformation efficiency and mutability in the wild type strain of . DHT + AP or DHT + Gap containing cluster demonstrated relatively low mutation frequency. On the other hand, in the case of an AP + AP or Gap + AP cluster, in which a base damage is absent, transformation efficiencies were significantly reduced. From these results it is suggested that, when either 8-oxoG or DHT is initially excised from a cluster containing 8-oxoG and DHT, the modified base remaining within the resulting damage will not be converted into an AP site or to a single strand break in vivo.