title: Role of the Flt-1 receptor tyrosine kinase in regulating the assembly of vascular endothelium.
abstract: The vascular endothelial growth factor (VEGF) and its high-affinity binding receptors, the tyrosine kinases Flt-1 and Flk-1, are thought to be important for the development of embryonic vasculature. Here we report that Flt-1 is essential for the organization of embryonic vasculature, but is not essential for endothelial cell differentiation. Mouse embryos homozygous for a targeted mutation in the flt-1 locus, flt-1lcz, formed endothelial cells in both embryonic and extra-embryonic regions, but assembled these cells into abnormal vascular channels and died in utero at mid-somite stages. At earlier stages, the blood islands of flt-1lcz homozygotes were abnormal, with angioblasts in the interior as well as on the periphery. We suggest that the Flt-1 signalling pathway may regulate normal endothelial cell-cell or cell-matrix interactions during vascular development.
authors.affiliation: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: G H
authors.initials: GH
authors.lastname: Fong
authors.forename: J
authors.initials: J
authors.lastname: Rossant
authors.forename: M
authors.initials: M
authors.lastname: Gertsenstein
authors.forename: M L
authors.initials: ML
authors.lastname: Breitman
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D017931:DNA Primers; D004622:Embryo, Mammalian / Q000098:blood supply; D016228:Endothelial Growth Factors / Q000502:physiology; D004730:Endothelium, Vascular / Q000166:cytology / Q000196:embryology*; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008222:Lymphokines / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D013234:Stem Cells; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors
chemical_list: D017931:DNA Primers; D016228:Endothelial Growth Factors; D008222:Lymphokines; D011518:Proto-Oncogene Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020794:Receptor Protein-Tyrosine Kinases; D040281:Vascular Endothelial Growth Factor Receptor-1