title: Linking H3K79 trimethylation to Wnt signaling through a novel Dot1-containing complex (DotCom).
abstract: Epigenetic modifications of chromatin play an important role in the regulation of gene expression. KMT4/Dot1 is a conserved histone methyltransferase capable of methylating chromatin on Lys79 of histone H3 (H3K79). Here we report the identification of a multisubunit Dot1 complex (DotCom), which includes several of the mixed lineage leukemia (MLL) partners in leukemia such as ENL, AF9/MLLT3, AF17/MLLT6, and AF10/MLLT10, as well as the known Wnt pathway modifiers TRRAP, Skp1, and beta-catenin. We demonstrated that the human DotCom is indeed capable of trimethylating H3K79 and, given the association of beta-catenin, Skp1, and TRRAP, we investigated, and found, a role for Dot1 in Wnt/Wingless signaling in an in vivo model system. Knockdown of Dot1 in Drosophila results in decreased expression of a subset of Wingless target genes. Furthermore, the loss of expression for the Drosophila homologs of the Dot1-associated proteins involved in the regulation of H3K79 shows a similar reduction in expression of these Wingless targets. From yeast to human, specific trimethylation of H3K79 by Dot1 requires the monoubiquitination of histone H2B by the Rad6/Bre1 complex. Here, we demonstrate that depletion of Bre1, the E3 ligase required for H2B monoubiquitination, leads specifically to reduced bulk H3K79 trimethylation levels and a reduction in expression of many Wingless targets. Overall, our study describes for the first time the components of DotCom and links the specific regulation of H3K79 trimethylation by Dot1 and its associated factors to the Wnt/Wingless signaling pathway.
authors.affiliation: Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.
authors.forename: Man
authors.initials: M
authors.lastname: Mohan
authors.forename: Hans-Martin
authors.initials: HM
authors.lastname: Herz
authors.forename: Yoh-Hei
authors.initials: YH
authors.lastname: Takahashi
authors.forename: Chengqi
authors.initials: C
authors.lastname: Lin
authors.forename: Ka Chun
authors.initials: KC
authors.lastname: Lai
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Michael P
authors.initials: MP
authors.lastname: Washburn
authors.forename: Laurence
authors.initials: L
authors.lastname: Florens
authors.forename: Ali
authors.initials: A
authors.lastname: Shilatifard
mesh_terms: D000818:Animals; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051153:Wnt Proteins / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D006657:Histones; D029701:Saccharomyces cerevisiae Proteins; D051153:Wnt Proteins; C473477:DOT1L protein, human; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase