DNA mismatch repair proteins: potential guardians against genomic instability and tumorigenesis induced by ultraviolet photoproducts.

In addition to their established role in repairing post-replicative DNA errors, DNA mismatch repair proteins contribute to cell cycle arrest and apoptosis in response to a wide range of exogenous DNA damage (e.g., alkylation-induced lesions). The role of DNA mismatch repair in response to ultraviolet-induced DNA damage has been historically controversial. Recent data, however, suggest that DNA mismatch repair proteins probably do not contribute to the removal of ultraviolet-induced DNA damage, but may be important in suppressing mutagenesis, effecting apoptosis, and suppressing tumorigenesis following exposure to ultraviolet radiation.