Histone H3-K9 methyltransferase, plant (IPR025794)

Short name: Hist-Lys_N-MeTrfase_plant

Overlapping homologous superfamilies

Family relationships



In general, members of this family methylate 'Lys-9' of histone H3. It also methylates 'Lys-27' of histone H3 [PMID: 15546353] and 'Lys-20' of H4, and cytosine [PMID: 15775980]. H3 'Lys-9' methylation represents a specific tag for epigenetic transcriptional repression [PMID: 15574848].

This enzyme plays a central role in gene silencing [PMID: 16384625]. The silencing mechanism via DNA CpNpG methylation requires the targeting of chromomethylase CMT3 to methylated histones, probably through an interaction with an heterochromatin protein 1-like adapter. Arabidopsis homologue SUVH4 is directly required for the maintenance of the DNA CpNpG and asymmetric methylation. It is also involved in the silencing of transposable elements [PMID: 11898023, PMID: 15457214, PMID: 15598823, PMID: 16277745, PMID: 16287862].

Methyltransferases (EC 2.1.1.-) constitute an important class of enzymes present in every life form. They transfer a methyl group most frequently from S-adenosyl L-methionine (SAM or AdoMet) to a nucleophilic acceptor such as oxygen leading to S-adenosyl-L-homocysteine (AdoHcy) and a methylated molecule [PMID: 16225687, PMID: 21858014, PMID: 12826405]. All these enzymes have in common a conserved region of about 130 amino acid residues that allow them to bind SAM [PMID: 7897657]. The substrates that are methylated by these enzymes cover virtually every kind of biomolecules ranging from small molecules, to lipids, proteins and nucleic acids [PMID: 16225687, PMID: 21858014, PMID: 7897657]. Methyltransferase are therefore involved in many essential cellular processes including biosynthesis, signal transduction, protein repair, chromatin regulation and gene silencing [PMID: 16225687, PMID: 21858014, PMID: 12826405]. More than 230 families of methyltransferases have been described so far, of which more than 220 use SAM as the methyl donor.

GO terms

Biological Process

GO:0016571 histone methylation

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles