DNA mismatch repair (MMR) guards the integrity of the genome in virtually all cells. It contributes about 1000-fold to the overall fidelity of replication and targets mispaired bases that arise through replication errors, during homologous recombination, and as a result of DNA damage. Cells deficient in MMR have a mutator phenotype in which the rate of spontaneous mutation is greatly elevated, and they frequently exhibit microsatellite instability at mono- and dinucleotide repeats. The importance of MMR in mutation avoidance is highlighted by the finding that defects in MMR predispose individuals to hereditary nonpolyposis colorectal cancer. In addition to its role in postreplication repair, the MMR machinery serves to police homologous recombination events and acts as a barrier to genetic exchange between species.

中文翻译：

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DNA错配修复：分子机制和生物学功能。

DNA错配修复（MMR）可以保护几乎所有细胞中的基因组完整性。它对复制的总体保真度贡献约1000倍，并靶向因复制错误，同源重组期间以及DNA破坏而产生的错配碱基。缺乏MMR的细胞具有突变表型，其中自发突变的速率大大提高，并且它们经常在单核苷酸和二核苷酸重复序列上表现出微卫星不稳定性。MMR缺陷易使个体易患遗传性非息肉性结直肠癌，这一发现凸显了MMR在避免突变中的重要性。MMR机制除了在复制后修复中发挥作用外，还用于监管同源重组事件，并成为种间遗传交换的障碍。