title: Endothelium-specific Cre recombinase activity in flk-1-Cre transgenic mice.
abstract: The use of the Cre-loxP recombination system allows the conditional inactivation of genes in mice. The availability of transgenic mice in which the Cre recombinase expression is highly cell type specific is a prerequisite to successfully use this system. We previously have characterized regulatory regions of the mouse flk-1 gene sufficient for endothelial cell-specific expression of the LacZ reporter gene in transgenic mice. These regions were fused to the Cre recombinase gene, and transgenic mouse lines were generated. In the resulting flk-1-Cre transgenic mice, specificity of Cre activity was determined by cross-breeding with the reporter mouse lines Rosa26R or CAG-CAT-LacZ. We examined double-transgenic mice at different stages of embryonic development (E9.5-E16.5) and organs of adult animals by LacZ staining. Strong endothelium-specific staining of most vascular beds was observed in embryos older than E11.5 in one or E13.5 in a second line. In addition, the neovasculature of experimental BFS-1 tumors expressed the transgene. These lines will be valuable for the conditional inactivation of floxed target genes in endothelial cells of the embryonic vascular system.
authors.affiliation: Department of Molecular Cell Biology, Max Planck Institute for Physiological and Clinical Research, Bad Nauheim, Germany.
authors.forename: Alexander H
authors.initials: AH
authors.lastname: Licht
authors.forename: Sabine
authors.initials: S
authors.lastname: Raab
authors.forename: Ursula
authors.initials: U
authors.lastname: Hofmann
authors.forename: Georg
authors.initials: G
authors.lastname: Breier
mesh_terms: D000818:Animals; D019677:Artificial Gene Fusion; D045744:Cell Line, Tumor; D004622:Embryo, Mammalian / Q000166:cytology / Q000201:enzymology; D004727:Endothelium / Q000196:embryology / Q000201:enzymology*; D004742:Enhancer Elements, Genetic / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D017930:Genes, Reporter / Q000502:physiology; D019426:Integrases / Q000235:genetics* / Q000378:metabolism*; D007763:Lac Operon / Q000235:genetics / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D009928:Organ Specificity; D011401:Promoter Regions, Genetic / Q000502:physiology*; D019076:Transgenes / Q000502:physiology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D014764:Viral Proteins; D040301:Vascular Endothelial Growth Factor Receptor-2; C045073:Cre recombinase; D019426:Integrases