Stopped for repairs

The tumor suppressor protein p53 is intimately involved in the cellular response to DNA damage, controlling cell cycle arrest, apoptosis and the transcriptional induction of DNA damage inducible genes. A transcriptional target of p53, Gadd45, was recently found to bind to PCNA, a component of DNA replication/repair complexes, thereby implicating Gadd45 in DNA metabolism. Using biochemical assays, a role for Gadd45 in excision repair in vitro has been demonstrated. Antisense experiments have also indicated an in vivo role for the GADD45 gene in UV-irradiation survival. These discoveries establish a link between p53 and DNA repair through Gadd45.