Histone methylation, first discovered in 1964, is a relatively stable post-translational modification (PTM) type, which derived from the interaction between the protein side chain with S-adenosyl methionine (SAM). This epigenetic modification, catalyzed by histone methyltransferases (HMTs), can occur at various sites of histones, but mainly occurs at the N-terminal lysine and arginine residues of H3 and H4, and it can be controlled by multiple positive and negative regulatory proteins to activate or inhibit transcription. This PTM is a very important and widespread chromatin modification that regulates gene expression by affecting the precise integration of chromatin or signal transduction, thereby affecting a variety of physiological processes in cells.
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