title: MLL-AF4 binds directly to a BCL-2 specific enhancer and modulates H3K27 acetylation.
abstract: Survival rates for children and adults carrying mutations in the Mixed Lineage Leukemia (MLL) gene continue to have a very poor prognosis. The most common MLL mutation in acute lymphoblastic leukemia is the t(4;11)(q21;q23) chromosome translocation that fuses MLL in-frame with the AF4 gene producing MLL-AF4 and AF4-MLL fusion proteins. Previously, we found that MLL-AF4 binds to the BCL-2 gene and directly activates it through DOT1L recruitment and increased H3K79me2/3 levels. In the study described here, we performed a detailed analysis of MLL-AF4 regulation of the entire BCL-2 family. By measuring nascent RNA production in MLL-AF4 knockdowns, we found that of all the BCL-2 family genes, MLL-AF4 directly controls the active transcription of both BCL-2 and MCL-1 and also represses BIM via binding of the polycomb group repressor 1 (PRC1) complex component CBX8. We further analyzed MLL-AF4 activation of the BCL-2 gene using Capture-C and identified a BCL-2-specific enhancer, consisting of two clusters of H3K27Ac at the 3' end of the gene. Loss of MLL-AF4 activity results in a reduction of H3K79me3 levels in the gene body and H3K27Ac levels at the 3' BCL-2 enhancer, revealing a novel regulatory link between these two histone marks and MLL-AF4-mediated activation of BCL-2.
authors.affiliation: Weatherall Institute of Molecular Medicine, MRC Molecular Haematology Unit, University of Oxford, Headington, Oxford, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Godfrey
authors.affiliation: Weatherall Institute of Molecular Medicine, MRC Molecular Haematology Unit, University of Oxford, Headington, Oxford, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Kerry
authors.affiliation: Weatherall Institute of Molecular Medicine, MRC Molecular Haematology Unit, University of Oxford, Headington, Oxford, UK.
authors.forename: Ross
authors.initials: R
authors.lastname: Thorne
authors.affiliation: Weatherall Institute of Molecular Medicine, Computational Biology Research Group, University of Oxford, Headington, Oxford, UK.
authors.forename: Emmanouela
authors.initials: E
authors.lastname: Repapi
authors.affiliation: Weatherall Institute of Molecular Medicine, MRC Molecular Haematology Unit, University of Oxford, Headington, Oxford, UK.
authors.forename: James O J
authors.initials: JO
authors.lastname: Davies
authors.affiliation: Weatherall Institute of Molecular Medicine, MRC Molecular Haematology Unit, University of Oxford, Headington, Oxford, UK.
authors.forename: Marta
authors.initials: M
authors.lastname: Tapia
authors.affiliation: Weatherall Institute of Molecular Medicine, MRC Molecular Haematology Unit, University of Oxford, Headington, Oxford, UK.
authors.forename: Erica
authors.initials: E
authors.lastname: Ballabio
authors.affiliation: Weatherall Institute of Molecular Medicine, MRC Molecular Haematology Unit, University of Oxford, Headington, Oxford, UK.
authors.forename: Jim R
authors.initials: JR
authors.lastname: Hughes
authors.affiliation: Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA.
authors.forename: Huimin
authors.initials: H
authors.lastname: Geng
authors.affiliation: Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Marina
authors.initials: M
authors.lastname: Konopleva
authors.affiliation: Weatherall Institute of Molecular Medicine, MRC Molecular Haematology Unit, University of Oxford, Headington, Oxford, UK. Electronic address: thomas.milne@imm.ox.ac.uk.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Milne
mesh_terms: D000107:Acetylation; D000072224:Bcl-2-Like Protein 11 / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D004742:Enhancer Elements, Genetic; D020869:Gene Expression Profiling; D015973:Gene Expression Regulation, Leukemic; D059014:High-Throughput Nucleotide Sequencing; D006657:Histones / Q000378:metabolism*; D006801:Humans; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000235:genetics; D051788:Myeloid-Lymphoid Leukemia Protein / Q000378:metabolism*; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D063150:Polycomb Repressive Complex 1 / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D014178:Translocation, Genetic
chemical_list: D000072224:Bcl-2-Like Protein 11; C570428:CBX8 protein, human; D018797:Cell Cycle Proteins; D006657:Histones; C113855:MLL-AF4 fusion protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D015514:Oncogene Proteins, Fusion; C116662:PRC1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D051788:Myeloid-Lymphoid Leukemia Protein; D063150:Polycomb Repressive Complex 1