The protein encoded by this gene is a histone methyltransferase that is part of the E2F6 complex, which represses transcription. The encoded protein methylates the Lys-9 position of histone H3, which tags it for transcriptional repression. This protein may be involved in the silencing of MYC- and E2F-responsive genes and therefore could play a role in the G0/G1 cell cycle transition. Defects in this gene are a cause of chromosome 9q subtelomeric deletion syndrome (9q-syndrome, also known as Kleefstra syndrome). Alternative splicing results in multiple transcript variants.