Mammalian single-strand break repair: mechanisms and links with chromatin.

Thousands of cellular single-strand breaks (SSBs) arise in cells each day, from attack of deoxyribose and DNA bases by reactive oxygen species and other electrophilic molecules, and from the intrinsic instability of DNA. If not repaired, SSBs can disrupt transcription and replication and can be converted into potentially clastogenic and/or lethal DNA double-strand breaks. Here, I present an updated model for the repair of SSBs, and speculate on the possible impact of chromatin structure and remodelling on single-strand break repair (SSBR) processes.