Contribution of base lesions to radiation-induced clustered DNA damage: Implication for models of radiation response

Biophysical modeling of radiation-induced DNA damage shows that significant yields of clustered DNA damage are formed after energy deposition by a sin gle radiation track. To date, the majority of studies on radiation-induced DNA damage in cells have concentrated on determination of the yields of sin gle- and double-strand breaks (DSBs), the latter representing one type of c lustered DNA damage. It was recognized, however, that clustered DNA damage, which does not contain a DSB, might contain a combination of DNA base lesi ons and single-strand breaks in proximity. This mini-review discusses some of the recent experimental data confirming the induction of non-DSB, cluste red DNA damage by radiation. (C) 2001 by Radiation Research Society.