ABSTRACT
Activation of DNA damage-dependent poly(ADP-ribose) polymerases (PARP-1, -2) is an immediate cellular reaction to DNA strand breakage as induced by alkylating agents, ionizing radiation, or oxidants. The resulting formation of protein-bound poly(ADP-ribose) (PAR) facilitates survival of proliferating cells under conditions of DNA damage probably via its contribution to DNA base excision repair and single-strand break repair. The role of PARP-1 during the repair of single-strand breaks in mammalian cells is now better understood, not only in vitro where PARP-1 activity facilitates the whole process, but also in living cells where PAR synthesis at sites of DNA lesions plays an essential role in the recruitment kinetics of one key player: X-ray cross-complementing factor 1. This review summarizes our present knowledge of a cellular response pathway to DNA damage specific for higher eukaryotes.
