During periods of genotoxic stress, the cyclin-dependent kinase inhibitor p21waf1cip1 (hereafter referred to as p21) is transcriptionally up-regulated by the p53 tumor suppressor and subsequently plays a key role in cellular growth arrest. Investigations have also indicated that p21 may regulate nucleotide excision repair, a critical pathway that removes carcinogenic DNA damage induced by UV li...

Largely on the basis of studies using the potent clastogen ionizing radiation, it has been widely assumed that up-regulation of the cyclin-dependent kinase inhibitor p21(waf1cip1) in cultured cells exposed to DNA-damaging agents is contingent upon the presence of functional p53 tumor suppressor protein. Nevertheless, we demonstrate here that the model mutagen 254-nm UV light induces p21(waf1cip...