Figure 1.

Main epigenetic mechanisms involved in gene expression regulation. DNA methylation consists of the addition of a methyl group in cytosine present in a cytosine–phosphate–guanine (CpG) dinucleotide. Histone post-translational modifications comprise alterations in histone tails such as methylation, acetylation, phosphorylation, and ubiquitination. Histone variants differ in few amino acids from canonical histones and regulate chromatin remodeling and histone post-translational modifications. Chromatin-remodeling complexes regulate the nucleosome structure by removing, relocating, and shifting histones.