[The roles of histone lysine methylation in epigenetic regulation].

Histone lysine methylation plays a key role in epigenetic regulation.There are five lysines within histone H3(K4, K9, K27, K36, K79). Besides, one lysine within histone H4(K20) has been shown to be methylated by specific histone lysine methyltransferase. Methylation at H3-K9 is associated with transcriptional repression, while methylation at H3-K4 and H3-K36 is associated with transcriptional activation. The methylation of histone H3-K27 was proved to be linked to several silencing phenomena including homeotic-gene silencing, X inactivation and genomic imprinting. H3-K79 methylation plays a role in DNA repair and transcriptional activation, and the extent and biological significance of histone de-methylation will surely attract great attention.