title: Regulation of the lmo2 promoter during hematopoietic and vascular development in zebrafish.
abstract: The Lmo2 transcription factor, a T-cell oncoprotein, is required for both hematopoiesis and angiogenesis. To investigate the fate of lmo2-expressing cells and the transcriptional regulation of lmo2 in vivo, we generated stable transgenic zebrafish that express green fluorescent protein (EGFP) or DsRed under the control of an lmo2 promoter. A 2.5-kb fragment contains the cis-regulatory elements required to recapitulate endogenous lmo2 expression in embryonic hematopoietic and vascular tissues. We further characterized embryonic Lmo2+ cells through transplantation into vlad tepes (vlt), an erythropoietic mutant. These Lmo2+ primitive wave donor cells differentiated into circulating hematopoietic cells and extended the life span of vlt recipients, but did not demonstrate long-term repopulation of the erythroid lineage. Promoter analysis identified a 174-bp proximal promoter that was sufficient to recapitulate lmo2 expression. This element contains critical ETS-binding sites conserved between zebrafish and pufferfish. Furthermore, we show that ets1 is coexpressed with lmo2, and overexpression experiments indicate that ets1 can activate the lmo2 promoter through this element. Our studies elucidate the transcriptional regulation of this key transcription factor, and provide a transgenic system for the functional analysis of blood and blood vessels in zebrafish.
authors.affiliation: Division of Hematology/Oncology, Children's Hospital of Boston, Department of Pediatrics, Boston, MA 02115, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhu
authors.forename: David
authors.initials: D
authors.lastname: Traver
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Davidson
authors.forename: Anthony
authors.initials: A
authors.lastname: Dibiase
authors.forename: Christine
authors.initials: C
authors.lastname: Thisse
authors.forename: Bernard
authors.initials: B
authors.lastname: Thisse
authors.forename: Stephen
authors.initials: S
authors.lastname: Nimer
authors.forename: Leonard I
authors.initials: LI
authors.lastname: Zon
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001808:Blood Vessels / Q000196:embryology / Q000378:metabolism; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D004912:Erythrocytes / Q000378:metabolism / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000502:physiology; D006413:Hematopoietic System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D060588:LIM Domain Proteins; D008667:Metalloproteins / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic / Q000502:physiology*; D011401:Promoter Regions, Genetic; D050784:Proto-Oncogene Protein c-ets-1 / Q000096:biosynthesis; D014157:Transcription Factors; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins
chemical_list: D004268:DNA-Binding Proteins; D060588:LIM Domain Proteins; D008667:Metalloproteins; D050784:Proto-Oncogene Protein c-ets-1; D014157:Transcription Factors; D029961:Zebrafish Proteins; C513186:lmo2 protein, zebrafish