MLH1 Gene

The MLH1 gene (MLH1 stands for "MutS Homolog1") is a protein-coding gene located on chromosome 3p22.2.

The protein encoded by this gene can heterodimerize with the mismatch repair endonuclease PMS2 to form MutL alpha, which is part of the DNA mismatch repair system. When MutL alpha is bound by MutS beta and some accessory proteins, the PMS2 subunit of MutL alpha induces a single-strand break near DNA mismatches, which is an entry point for exonuclease degradation. The encoded protein is also involved in DNA damage signaling and can heterodimerize with the DNA mismatch repair protein MLH3 to form MutL gamma, which is involved in meiosis.

MLH1 is a tumor suppressor gene involved in DNA mismatch repair. Germline mutations in this gene are known to cause Lynch syndrome and its variant Muir-Torre syndrome. The most common malignancies in Lynch syndrome are colorectal and endometrial carcinomas. In addition to germline mutations, somatic mutations in this gene have also been described in colorectal and endometrial carcinomas.

1. Sameer AS et al. (2014) Mismatch repair pathway: molecules, functions, and role in colorectal carcinogenesis. Eur J Cancer Prev. 23:246-257.
2. Traver S et al (2015) MCM9 Is Required for Mammalian DNA Mismatch Repair. Mol Cell 59:831-839.
3. Truninger K et al (2005) Immunohistochemical analysis reveals high frequency of PMS2 defects in colorectal cancer. Gastroenterology 128:1160-1171