Mammalian DNA mismatch repair

DNA mismatch repair (MMR) is one of multiple replication, repair, and recom bination processes that are required to maintain genomic stability in proka ryotes and eukaryotes. In the wake of the discoveries that hereditary nonpo lyposis colorectal cancer (HNPCC) and other human cancers are associated wi th mutations in MMR genes, intensive efforts are under way to elucidate the biochemical functions of mammalian MutS and MutL homologs, and the consequ ences of defects in these genes. Genetic studies in cultured mammalian cell s and mice are proving to be instrumental in defining the relationship betw een the functions of MMR in mutation and tumor avoidance. Furthermore, thes e approaches have raised awareness that MMR homologs contribute to DNA dama ge surveillance, transcription-coupled repair, and recombinogenic and meiot ic processes.