title: Kruppel-like factor 2 cooperates with the ETS family protein ERG to activate Flk1 expression during vascular development.
abstract: The VEGF receptor, FLK1, is essential for differentiation of the endothelial lineage and for embryonic vascular development. Using comparative genomics, we have identified conserved ETS and Krüppel-like factor (KLF) binding sites within the Flk1 enhancer. In transgenic studies, mutation of either site results in dramatic reduction of Flk1 reporter expression. Overexpression of KLF2 or the ETS transcription factor ERG is sufficient to induce ectopic Flk1 expression in the Xenopus embryo. Inhibition of KLF2 function in the Xenopus embryo results in a dramatic reduction in Flk1 transcript levels. Furthermore, we show that KLF2 and ERG associate in a physical complex and that the two proteins synergistically activate transcription of Flk1. Since the ETS and KLF protein families have independently been recognized as important regulators of endothelial gene expression, cooperation between the two families has broad implications for gene regulation during development, normal physiology and vascular disease.
authors.affiliation: Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Stryder M
authors.initials: SM
authors.lastname: Meadows
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Salanga
authors.forename: Paul A
authors.initials: PA
authors.lastname: Krieg
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001808:Blood Vessels / Q000196:embryology* / Q000378:metabolism; D017124:Conserved Sequence; D017931:DNA Primers / Q000235:genetics; D042783:Endothelial Cells / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D051741:Kruppel-Like Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes; D011994:Recombinant Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
chemical_list: D017931:DNA Primers; C404162:Erg protein, Xenopus; D051741:Kruppel-Like Transcription Factors; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D014157:Transcription Factors; D029867:Xenopus Proteins; D049452:Green Fluorescent Proteins; D040301:Vascular Endothelial Growth Factor Receptor-2