Background
Histone post-translational modifications (PTMs) are key epigenetic mechanisms that modulate chromatin structures, collectively known as the “histone code”. The PTMs on histone including acetylation, methylation, phosphorylation, and novel acylations directly affect the accessibility of chromatin to transcription factors and other epigenetic regulators, altering genome stability and gene transcription. Histone methylation occurs primarily at lysine and arginine residues on the amino terminal of core histones. Histone methylation can either enhance or repress gene transcription, depending on the specific amino acid modified and the number ofmethyl groups attached. Lysine methylation can occur in mono-, di-, or tri-methylated forms, while arginine methylation exists in mono, di-symmetric, or di-asymmetric forms. Key methylation sites include histone H3 (Lys4, 9, 27, 36, 79) and histone H4 (Lys20) for lysine methylation, while histone H3 (Arg2, 8, 17, 26) and histone H4 (Arg3) are primary sites for arginine methylation. The dynamic regulation of histone methylation is controlled by histone methyltransferases (HMTs) and histone demethylases (HDMs).
Cellular location
Nucleus
