A role for the MLL fusion partner ENL in transcriptional elongation and chromatin modification.
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.
Mueller
Dorothee
D
Department of Genetics, University Erlangen, Erlangen, Germany.
Bach
Christian
C
Zeisig
Deniz
D
Garcia-Cuellar
Maria-Paz
MP
Monroe
Sara
S
Sreekumar
Arun
A
Zhou
Rong
R
Nesvizhskii
Alexey
A
Chinnaiyan
Arul
A
Hess
Jay L
JL
Slany
Robert K
RK
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
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