Epigenetics: interaction of DNA methylation and chromatin.

Epigenetic regulation is the mechanism by which gene function is selectively activated or inactivated in the cells. It provides higher-ordered and more specified genetic information, compared with the whole genome itself. Recently, a variety of regulatory proteins including DNA methyltransferases, methyl-CpG binding proteins, histone-modifying enzymes, chromatin remodeling factors, and their multimolecular complexes have been identified. These facilitate our understanding of the molecular basis for transcription, DNA replication, mutation and repair, DNA recombination, and chromosome dynamics, which are crucial for normal cell regulation. Abnormalities in the epigenetic states represent human disease phenotypes, especially developmental defects and tumorigenesis. Therefore, epigenetics will become the focus and a major target for emerging biological and medical discoveries.