Histones are key regulators of gene expression, through numerous well-known chemical modifications. These include acetylation, phosphorylation, methylation, and ubiquitylation. For example, methylating and/or acetylating specific lysine residues of the nucleosomal cores of histones, such as lysine8, alter the chromatin structure, through interacting with the methylation machinery, and gene expression (1).
DNA Methylation Machinery, Histone Deacetylases and Histone Methyltransferases
Histone deacetylases and histone methyltransferases are the two key regulators of histone modifications.
(1) Wang Y, et al. 2004. Beyond the double helix: writing and reading the histone code. Novartis Found Symp. 259, 3-17