P53 MODULATION OF TFIIH-ASSOCIATED NUCLEOTIDE EXCISION-REPAIR ACTIVITY

p53 has pleiotropic functions including control of genomic plasticity and integrity. Here we report that p53 can bind to several transcripti on factor IIH-associated factors, including transcription-repair facto rs, XPD (Rad3) and XPB, as well as CSB involved in strand-specific DNA repair, via its C-terminal domain. We also found that wild-type, but not Arg273His mutant p53 inhibits XPD (Rad3) and XPB DNA helicase acti vities. Moreover, repair of UV-induced dimers is slower in Li-Fraumeni syndrome cells (heterozygote p53 mutant) than in normal human cells. Our findings indicate that p53 may play a direct role in modulating nu cleotide excision repair pathways.