Eukaryotic DNA mismatch repair

Eukaryotic mismatch repair (MMR) has been shown to require two different he terodimeric complexes of MutS-related proteins: MSH2-MSH3 and MSH2-MSH6. Th ose two complexes have different mispair recognition properties and differe nt abilities to support MMR. Alternative models have been proposed for how these MSH complexes function in MMR. Two different heterodimeric complexes of MutL-related proteins, MLH1-PMS1 (human PMS2) and MLH1-MLH3 (human PMS1) also function in MMR and appear to interact with other MMR proteins includ ing the MSH complexes and replication factors. A number of other proteins h ave been implicated in MMR, including DNA polymerase delta, RPA (replicatio n protein A), PCNA (proliferating cell nuclear antigen), RFC (replication f actor C), Exonuclease 1, FEN1 (RAD27) and the DNA polymerase delta and epsi lon associated exonucleases. MMR proteins have also been shown to function in other types of repair and recombination that appear distinct from MMR. M MR proteins function in these processes in conjunction with components of n ucleotide excision repair (NER) and, possibly, recombination.