Role of DNA methylation in the regulation of cell function

The methylation of DNA helps stabilize chromatin in an inactive configurati on and inhibits gene transcription. This mechanism of gene regulation is in volved in essential genetic events including differentiation, genomic impri nting, and X chromosome inactivation. The alteration of methylation pattern s can result in abnormal gene expression, with significant pathologic effec ts including carcinogenesis, autoimmunity, and some of the changes in gene expression associated with aging. The mechanisms establishing, maintaining, and modifying methylation patterns in normal and pathologic states are onl y now becoming understood, as are the mechanisms relating DNA methylation t o gene expression and chromosome inactivation. Further characterization of these mechanisms holds promise for delaying or preventing the changes in me thylation patterns that contribute to cancer, autoimmunity and aging.