Post-irradiation chemical processing of DNA damage generates double-strand breaks in cells already engaged in repair.

ABSTRACT: In cells exposed to ionizing radiation (IR), double-strand breaks (DSBs) form within clustered-damage sites from lesions disrupting the DNA sugar-phosphate backbone. It is commonly assumed that these DSBs form promptly and are immediately detected and processed by the cellular DNA damage response (DDR) apparatus. This assumption is questioned by the observation that after irradiation of naked DNA, a fraction of DSBs forms minutes to hours after exposure as a result of temperature dependent, chemical processing of labile sugar lesions. Excess DSBs also form when IR-exposed cells are processed at 50°C, but have been hitherto considered method-related artifact. Thus, it remains unknown whether DSBs actually develop in cells after IR exposure from chemically labile damage. Here, we show that i

SUBMITTER: Singh SK 

PROVIDER: S-EPMC3201859 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature