Role of PARP-1 in repair of UV-damaged DNA in mammalian Cells

Poly (ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme that is activated strongly in response to DNA damage to form polymers of ADP-ribose (PAR), which post-translationally modify different DNA structure and function related proteins in the vicinity of DNA damage. Recent studies are revealing new functions of this old enzyme in mammalian and higher eukaryotic cells, which range from DNA repair to cell death. While its role in the DNA repair by base excision repair pathway and some pathways of DNA double strand break repair is better characterized, there was not much known about its role in the most versatile DNA repair pathway called nucleotide excision repair (NER) that repairs DNA damage caused by UV, drugs and many other chemicals. Recent studies are including those from Prof. Shah's team now show that PARP-1 is implicated in the early lesion recognition phase of NER by sensing these types of DNA damages in the chromatin context in mammalian cells, interacting with some of the key early NER proteins, and facilitating the downstream repair events. The novel role of PARP-1 in mammalian NER could be exploited for protection of skin against sunlight-induced skin cancers.