title: A role for the MLL fusion partner ENL in transcriptional elongation and chromatin modification.
abstract: Chimeric proteins joining the histone methyltransferase MLL with various fusion partners trigger distinctive lymphoid and myeloid leukemias. Here, we immunopurified proteins associated with ENL, a protein commonly fused to MLL. Identification of these ENL-associated proteins (EAPs) by mass spectrometry revealed enzymes with a known role in transcriptional elongation (RNA polymerase II C-terminal domain kinase [RNAPolII CTD] positive transcription elongation factor b [pTEFb]), and in chromatin modification (histone-H3 methyltransferase DOT1L) as well as other frequent MLL partners (AF4, AF5q31, and LAF4), and polycomb group members (RING1, CBX8, and BCoR). The composition of EAP was further verified by coimmunoprecipitation, 2-hybrid analysis, pull-down, and colocalization experiments. Purified EAP showed a histone H3 lysine 79-specific methylase activity, displayed a robust RNAPolII CTD kinase function, and counteracted the effect of the pTEFb inhibitor 5,6-dichloro-benzimidazole-riboside. In vivo, an ENL knock-down diminished genome-wide as well as gene-specific H3K79 dimethylation, reduced global run-on elongation, and inhibited transient transcriptional reporter activity. According to structure-function data, DOT1L recruitment was important for transformation by the MLL-ENL fusion derivative. These results suggest a function of ENL in histone modification and transcriptional elongation.
authors.affiliation: Department of Genetics, University Erlangen, Erlangen, Germany.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Mueller
authors.forename: Christian
authors.initials: C
authors.lastname: Bach
authors.forename: Deniz
authors.initials: D
authors.lastname: Zeisig
authors.forename: Maria-Paz
authors.initials: MP
authors.lastname: Garcia-Cuellar
authors.forename: Sara
authors.initials: S
authors.lastname: Monroe
authors.forename: Arun
authors.initials: A
authors.lastname: Sreekumar
authors.forename: Rong
authors.initials: R
authors.lastname: Zhou
authors.forename: Alexey
authors.initials: A
authors.lastname: Nesvizhskii
authors.forename: Arul
authors.initials: A
authors.lastname: Chinnaiyan
authors.forename: Jay L
authors.initials: JL
authors.lastname: Hess
authors.forename: Robert K
authors.initials: RK
authors.lastname: Slany
mesh_terms: D000818:Animals; D002460:Cell Line; D042002:Chromatin Assembly and Disassembly; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D047468:Immunoprecipitation; D008780:Methyltransferases / Q000378:metabolism*; D051379:Mice; D033681:Mitochondrial Membrane Transport Proteins; D046912:Multiprotein Complexes / Q000032:analysis; D051788:Myeloid-Lymphoid Leukemia Protein; D009363:Neoplasm Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology*; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology*; D063150:Polycomb Repressive Complex 1; D063146:Polycomb-Group Proteins; D042925:Positive Transcriptional Elongation Factor B / Q000378:metabolism*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: C570428:CBX8 protein, human; C081448:MLLT1 protein, human; D033681:Mitochondrial Membrane Transport Proteins; D046912:Multiprotein Complexes; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D063146:Polycomb-Group Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; C473477:DOT1L protein, human; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; C570429:Cbx8 protein, mouse; D063150:Polycomb Repressive Complex 1; D042925:Positive Transcriptional Elongation Factor B