title: Bat3 facilitates H3K79 dimethylation by DOT1L and promotes DNA damage-induced 53BP1 foci at G1/G2 cell-cycle phases.
abstract: The methyltransferase DOT1L methylates histone H3 at K79 to facilitate specific biological events. H3K79 dimethylation (H3K79-2Me) by DOT1L influences the DNA damage response by promoting 53BP1 recruitment to DNA damage sites; however, it is unclear if this methylation is required as 53BP1 interacts with dimethylated H4 (H4K20-2Me) with a much higher affinity. We demonstrate that H3K79-2Me, while negligible during S-phase, is required for ionizing radiation (IR)-induced 53BP1 foci formation during G1/G2-phases when H4K20-2Me levels are low. Further, we describe an essential role for HLA-B-associated transcript 3 (Bat3) in regulating this process in U2OS cells. Bat3 co-localizes with DOT1L at histone H3, and Bat3 knockdown results in decreased DOT1L-H3 interaction and H3K79-2Me, leading to a reduction in IR-induced 53BP1 foci formation, defects in DNA repair and increased sensitivity to IR. We demonstrate that a conserved Bat3 ubiquitin-like motif and a conserved DOT1L ubiquitin-interacting motif promote DOT1L-Bat3 interaction to facilitate efficient H3K79-2Me and IR-induced 53BP1 foci formation during G1/G2-phases. Taken together, our findings identify a novel role for Bat3 in regulating DOT1L function, which plays a critical role in DNA damage response.
authors.affiliation: Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Wakeman
authors.forename: Qinhong
authors.initials: Q
authors.lastname: Wang
authors.forename: Junjie
authors.initials: J
authors.lastname: Feng
authors.forename: Xiao-Fan
authors.initials: XF
authors.lastname: Wang
mesh_terms: D045744:Cell Line, Tumor; D004249:DNA Damage; D004260:DNA Repair; D016193:G1 Phase; D016195:G2 Phase; D057809:HEK293 Cells; D006367:HeLa Cells; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism*; D000071857:Tumor Suppressor p53-Binding Protein 1
chemical_list: C092009:BAG6 protein, human; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; C473477:DOT1L protein, human; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase