[Regulation of gene expression: how do epigenetic mechanisms work].

Cell phenotype does not only depend on the nucleotide sequence, but is determined by those genes that are expressed and those that are not. One way to regulate this gene expression pattern is by modifying the chromatin structure via diverse epigenetic mechanisms. In the present article we present the most important epigenetic mechanisms: deoxyribonucleic acid methylation, histone post-translational modifications, non-coding ribonucleic acid mediated gene-silencing, ATP-dependent chromatin remodeling, and Polycomb and Trithorax group proteins.