title: Expression of the leukemia oncogene Lmo2 is controlled by an array of tissue-specific elements dispersed over 100 kb and bound by Tal1/Lmo2, Ets, and Gata factors.
abstract: The Lmo2 gene encodes a transcriptional cofactor critical for the development of hematopoietic stem cells. Ectopic LMO2 expression causes leukemia in T-cell acute lymphoblastic leukemia (T-ALL) patients and severe combined immunodeficiency patients undergoing retroviral gene therapy. Tightly controlled Lmo2 expression is therefore essential, yet no comprehensive analysis of Lmo2 regulation has been published so far. By comparative genomics, we identified 17 highly conserved noncoding elements, 9 of which revealed specific acetylation marks in chromatin-immunoprecipitation and microarray (ChIP-chip) assays performed across 250 kb of the Lmo2 locus in 11 cell types covering different stages of hematopoietic differentiation. All candidate regulatory regions were tested in transgenic mice. An extended LMO2 proximal promoter fragment displayed strong endothelial activity, while the distal promoter showed weak forebrain activity. Eight of the 15 distal candidate elements functioned as enhancers, which together recapitulated the full expression pattern of Lmo2, directing expression to endothelium, hematopoietic cells, tail, and forebrain. Interestingly, distinct combinations of specific distal regulatory elements were required to extend endothelial activity of the LMO2 promoter to yolk sac or fetal liver hematopoietic cells. Finally, Sfpi1/Pu.1, Fli1, Gata2, Tal1/Scl, and Lmo2 were shown to bind to and transactivate Lmo2 hematopoietic enhancers, thus identifying key upstream regulators and positioning Lmo2 within hematopoietic regulatory networks.
authors.affiliation: Department of Haematology, Cambridge Institute for Medical Research, Cambridge University, Cambridge, United Kingdom.
authors.forename: Josette-Renée
authors.initials: JR
authors.lastname: Landry
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bonadies
authors.forename: Sarah
authors.initials: S
authors.lastname: Kinston
authors.forename: Kathy
authors.initials: K
authors.lastname: Knezevic
authors.forename: Nicola K
authors.initials: NK
authors.lastname: Wilson
authors.forename: S Helen
authors.initials: SH
authors.lastname: Oram
authors.forename: Mary
authors.initials: M
authors.lastname: Janes
authors.forename: Sandie
authors.initials: S
authors.lastname: Piltz
authors.forename: Michelle
authors.initials: M
authors.lastname: Hammett
authors.forename: Jacinta
authors.initials: J
authors.lastname: Carter
authors.forename: Tina
authors.initials: T
authors.lastname: Hamilton
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Donaldson
authors.forename: Georges
authors.initials: G
authors.lastname: Lacaud
authors.forename: Jonathan
authors.initials: J
authors.lastname: Frampton
authors.forename: George
authors.initials: G
authors.lastname: Follows
authors.forename: Valerie
authors.initials: V
authors.lastname: Kouskoff
authors.forename: Berthold
authors.initials: B
authors.lastname: Göttgens
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000196:embryology / Q000378:metabolism; D050980:GATA Transcription Factors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D016678:Genome / Q000235:genetics; D060588:LIM Domain Proteins; D007938:Leukemia / Q000235:genetics / Q000378:metabolism*; D008667:Metalloproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D046888:Tissue Array Analysis; D015534:Trans-Activators / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D050980:GATA Transcription Factors; D060588:LIM Domain Proteins; D008667:Metalloproteins; D011518:Proto-Oncogene Proteins; D019098:Telomerase; D015534:Trans-Activators; C513188:Lmo2 protein, mouse