Received October 26, 2004; Revision received November 17, 2004
The main epigenetic mechanisms in regulation of gene expression are discussed. The definition of epigenetics and its specific mechanisms including DNA methylation and gene imprinting, modifications of nucleosomal histones associated with silencing or activation of gene transcription, RNA interference, chromosomal silencing, and the role of mobile elements are discussed.
KEY WORDS: epigenetics, imprinting, histone modifications, chromosomal silencing, heterochromatin, PcG proteins, forum domains, RNA interference, siRNA, miRNA, RISC, RITS, mobile elements