Histone-lysine N-methyltransferase SETD1B () is a histone methyltransferase that produces trimethylated histone H3 at 'Lys-4'. However, if 'Lys-9' residue is already methylated, 'Lys-4' will not be. The 'Lys-4' methylation is a tag for epigenetic transcriptional activation []. The SET1 complex contains either SETD1A or SETD1B.The SET1 complex is a methyltransferase that that produces trimethylated histone H3 at Lys(4). It is composed of at least the catalytic subunit (SETD1A or SETD1B), WDR5, WDR82, RBBP5, ASH2L/ASH2, CXXC1/CFP1, HCFC1 and DPY30 []. In yeast there is only one SET1 complex, but in mammals there are additional H3K4 methylases [].
This entry represents the RNA recognition motif (RRM) of Setd1B (also known as Set1B), a ubiquitously expressed vertebrates histone methyltransferase that exhibits high homology to yeast Set1. Set1B is localised to euchromatic nuclear speckles and associates with a complex containing six human homologues of the yeast Set1/COMPASS complex, including CXXC finger protein 1 (CFP1; homologous to yeast Spp1), Rbbp5 (homologous to yeast Swd1), Ash2 (homologous to yeast Bre2), Wdr5 (homologous to yeast Swd3), and Wdr82 (homologous to yeast Swd2). Set1B complex is a histone methyltransferase that produces trimethylated histone H3 at Lys4 [, ]. Set1B contains an N-terminal RNA recognition motif (RRM), an N-SET domain, and a C-terminal catalytic SET domain followed by a post-SET domain.
