A nucleotide excision repair master-switch: p53 regulated coordinate induction of global genomic repair genes

The tumor suppressor gene p53 is mutated in many human cancers. One of its major roles is as a transcription factor, and its many effector genes control key cellular processes including cell cycle checkpoints and apoptosis. An important role in DNA repair is also emerging for both p53 itself and some of its effector genes. The products of two p53-regulated genes, GADD45a and DDB2, are now known to participate in the global genomic repair (GGR) sub-pathway of nucleotide excision repair (NER). We recently reported the induction of a third GGR gene, XPC, following exposure of normal human peripheral blood lymphocytes to ?-rays. We now show that XPC is induced in a variety of human cell lines in response to both ionizing and ultra-violet (UV) radiation and alkylating agents, and that this induction requires wild-type p53.