This entry includes Sdc1 from yeasts, and its homologues, Dpy-30, from animals. Protein dpy-30 homologue (DPY30) is a component of the MLL1/MLL complex which trimethylates histone H3 at 'Lys-4' as a specific tag for epigenetic transcriptional activation []. DPY30 is also a component in MLL2/3 and MLL4/WBP7 methyltransferase-containing complexes [, ]and the SET1 complex []. DPY30 is found in the nucleus and the trans-Golgi network where it interacts with ARFGEF1 implying a role in endosomal trafficking []. This entry also includes C. elegans dpy-30, which is an essential component of the C. elegans dosage compensation machinery that reduces X chromosome transcript levels in hermaphrodites (XX) [].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 [].
In animals, histone-lysine N-methyltransferase SETD1A () is a histone methyltransferase that produces mono-, di-, and 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 [].
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 [].
The extended plant homeodomain (ePHD) zinc finger is characterized as Cys2HisCys5HisCys2His. This entry represents the ePHD finger of Histone-lysine N-methyltransferase 2A (KMT2A), which is a histone methyltransferase that belongs to the MLL subfamily of H3K4-specific histone lysine methyltransferases (KMT2). It regulates chromatin-mediated transcription through the catalysis of methylation of histone 3 lysine 4 (H3K4), and is frequently rearranged in acute leukemia []. KMT2A functions as the catalytic subunit in the MLL1 complex, which also contains WDR5, RbBP5, ASH2L and DPY30 as integral core subunits required for the efficient methylation activity of the complex [, ]. The MLL1 complex is highly active and specific for H3K4 methylation. KMT2A contains a CxxC (x for any residue) zinc finger domain, three PHD fingers, a Bromodomain domain, this extended PHD finger, two FY (phenylalanine tyrosine)-rich domains, and a SET (Suppressor of variegation, Enhancer of zeste, Trithorax) domain [].
The extended plant homeodomain (ePHD) zinc finger is characterized as Cys2HisCys5HisCys2His. This entry represents the ePHD finger of Histone-lysine N-methyltransferase 2B (KMT2B), also known as MLL2. KMT2B is a second human homologue of Drosophila trithorax, located on chromosome 19 [, ]. It belongs to the MLL subfamily of H3K4-specific histone lysine methyltransferases (KMT2) and is vital for normal mammalian embryonic development []. KMT2B functions as the catalytic subunit in the MLL2 complex, which contains WDR5, RbBP5, ASH2L and DPY30 as integral core subunits required for the efficient methylation activity of the complex. The MLL2 complex is highly active and specific for histone 3 lysine 4 (H3K4) methylation, which stimulates chromatin transcription in a SAM- and H3K4-dependent manner []. Moreover, KMT2B plays a critical role in memory formation by mediating hippocampal H3K4 di- and trimethylation []. It is also required for RNA polymerase II association and protection from DNA methylation at the MagohB CpG island promoter []. KMT2B contains a CxxC (x for any residue) zinc finger domain, three PHD fingers, this ePHD finger, two FY (phenylalanine tyrosine)-rich domains, and a SET (Suppressor of variegation, Enhancer of zeste, Trithorax) domain.
The COMPASS complex (complex proteins associated with Set1) is conserved in yeasts and in other eukaryotes up to humans. This entry represents Set1 and its homologues. Set1 is a methyltransferase and the catalytic component of the COMPASS that produces trimethylated histone H3 at Lys(4). The yeast COMPASS (Set1C) complex specifically mono-, di- and trimethylates histone H3 to form H3K4me1/2/3, which subsequently plays a role in telomere length maintenance and transcription elongation regulation [, , ]. In yeasts, the Set1C complex consists of Set1(2), Bre2(2), Spp1(2), Sdc1(1), Shg1(1), Swd1(1), Swd2(1), and Swd3(1) [, , , ].In animals, SETD1A/B are histone methyltransferases that produce mono-, di-, and 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 animal COMPASS complex is composed of at least the catalytic subunit (SETD1A or SETD1B), WDR5, WDR82, RBBP5, ASH2L/ASH2, CXXC1/CFP1, HCFC1 and DPY30 []. ATXR7, the Arabidopsis homologue to Set1, is required for the expression of the flowering repressors FLC and MADS-box genes of the MAF family [, ]. ATXR7 is also involved in the control of seed dormancy and germination [].
