The SCL gene specifies haemangioblast development from early mesoderm.
The SCL gene encodes a basic helix-loop-helix (bHLH) transcription factor that is essential for the development of all haematopoietic lineages. SCL is also expressed in endothelial cells, but its function is not essential for specification of endothelial progenitors and the role of SCL in endothelial development is obscure. We isolated the zebrafish SCL homologue and show that it was co-expressed in early mesoderm with markers of haematopoietic, endothelial and pronephric progenitors. Ectopic expression of SCL mRNA in zebrafish embryos resulted in overproduction of common haematopoietic and endothelial precursors, perturbation of vasculogenesis and concomitant loss of pronephric duct and somitic tissue. Notochord and neural tube formation were unaffected. These results provide the first evidence that SCL specifies formation of haemangioblasts, the proposed common precursor of blood and endothelial lineages. Our data also underline the striking similarities between the role of SCL in haematopoiesis/vasculogenesis and the function of other bHLH proteins in muscle and neural development.
University of Cambridge, Department of Haematology, MRC Centre, Hills Road, Cambridge CB2 2QH, UK.
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D000595:Amino Acid Sequence; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000502:physiology; D004730:Endothelium, Vascular / Q000196:embryology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D005809:Genes, Regulator / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D007684:Kidney Tubules / Q000196:embryology; D008648:Mesoderm / Q000737:chemistry / Q000166:cytology; D008969:Molecular Sequence Data; D017570:MyoD Protein / Q000235:genetics; D018919:Neovascularization, Physiologic; D009687:Nuclear Proteins; D051762:PAX2 Transcription Factor; D010802:Phylogeny; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000032:analysis; D017422:Sequence Analysis, DNA; D019170:Somites; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors / Q000235:genetics; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D017570:MyoD Protein; D009687:Nuclear Proteins; D051762:PAX2 Transcription Factor; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; D029961:Zebrafish Proteins; C497320:pax2a protein, zebrafish; C489367:tal1 protein, zebrafish; C512784:tcf15 protein, zebrafish