histone-lysine N-methyltransferase EHMT2; euchromatic histone-lysine N-methyltransferase 2; HLA-B-associated transcript 8; histone H3-K9 methyltransferase 3; H3-K9-HMTase 3; lysine N-methyltransferase 1C; protein G9a (EHMT2, BAT8, C6orf30, G9A, KMT1C, NG36)
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Function
- histone methyltransferase
- specifically mono- & dimethylates Lys-9 of histone H3 (H3K9me1 & H3K9me2, respectively) in euchromatin
- H3K9me represents a specific tag for epigenetic transcriptional repression by recruiting HP1 proteins to methylated histones
- weakly methylates Lys-27 of histone H3 (H3K27me)
- required for DNA methylation
- the histone methyltransferase activity is not required for DNA methylation, suggesting that these 2 activities function independently probably targeted to histone H3 by different DNA-binding proteins like E2F6, MGA, MAX &/or DP1
- may also methylate histone H1
- in addition to the histone methyltransferase activity, also methylates non-histone proteins:
- phosphorylated upon DNA damage, probably by ATM or ATR
- methylated at Lys-185; automethylated
- heterodimer; heterodimerizes with EHMT1/GLP
- interacts with GFI1B & WIZ
- part of the E2F6.com-1 complex in G0 phase
S-adenosyl-L-methionine + L-lysine-[[[A137031|histone]]] = S-adenosyl-L-homocysteine + N(6)-methyl-L-lysine-[[[A137031|histone]]]
Structure
- the SET domain mediates interaction with WIZ
- the ANK repeats bind H3K9me1 & H3K9me2
- belongs to the histone-lysine methyltransferase family, Suvar3-9 subfamily
- contains 7 ANK repeats
- contains 1 post-SET domain
- contains 1 pre-SET domain
- contains 1 SET domain
Compartment
- nucleus, chromosome
- associates with euchromatin
- does not associate with heterochromatin
Alternative splicing
Expression
- expressed in all tissues examined
- expressed in fetal liver, thymus, lymph node, spleen & peripheral blood leukocytes > bone marrow
Notes
- uncertain whether Met-1 or Met-21 is the initiator methionine