title: TAL1/SCL is expressed in endothelial progenitor cells/angioblasts and defines a dorsal-to-ventral gradient of vasculogenesis.
abstract: In this study we establish that TAL1/SCL, a member of the helix-loop-helix family of transcription factors, and an important regulator of the hematopoietic lineage in mice, is expressed in the endothelial lineage of avians. The earliest events of vascular development were examined using antibodies to TAL1/SCL, and the QH1 antibody, an established marker of quail endothelial cells. Analyses using double immunofluorescence confocal microscopy show that: (i) TAL1/SCL is expressed by both quail and chicken endothelial cells; (ii) TAL1/SCL expression precedes that of the QH1 epitope; and (iii) TAL1/SCL, but not QH1, expression defines a subpopulation of primordial cells within the splanchnic mesoderm. Collectively these data suggest that TAL1/SCL-positive/QH1-negative cells are angioblasts. Further, using TAL1/SCL expression as a marker of the endothelial lineage, we demonstrate that in addition to the previously described cranial-to-caudal gradient, there is a dorsal-to-ventral progression of vasculogenesis.
authors.affiliation: Department of Cell Biology and Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Drake
authors.forename: S J
authors.initials: SJ
authors.lastname: Brandt
authors.forename: T C
authors.initials: TC
authors.lastname: Trusk
authors.forename: C D
authors.initials: CD
authors.lastname: Little
mesh_terms: D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D001808:Blood Vessels / Q000196:embryology* / Q000378:metabolism*; D002642:Chick Embryo; D003370:Coturnix; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D006410:Hematopoiesis; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D011518:Proto-Oncogene Proteins; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D017931:DNA Primers; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C489366:Tal1 protein, mouse