title: Rasip1 is required for endothelial cell motility, angiogenesis and vessel formation.
abstract: Ras proteins are small GTPases that regulate cellular growth and differentiation. Components of the Ras signaling pathway have been shown to be important during embryonic vasculogenesis and angiogenesis. Here, we report that Rasip1, which encodes a novel Ras-interacting protein, is strongly expressed in vascular endothelial cells throughout development, in both mouse and frog. Similar to the well-characterized vascular markers VEGFR2 and PECAM, Rasip1 is specifically expressed in angioblasts prior to vessel formation, in the initial embryonic vascular plexus, in the growing blood vessels during angiogenesis and in the endothelium of mature blood vessels into the postnatal period. Rasip1 expression is undetectable in VEGFR2 null embryos, which lack endothelial cells, suggesting that Rasip1 is endothelial specific. siRNA-mediated reduction of Rasip1 severely impairs angiogenesis and motility in endothelial cell cultures, and morpholino knockdown experiments in frog embryos demonstrate that Rasip1 is required for embryonic vessel formation in vivo. Together, these data identify Rasip1 as a novel endothelial factor that plays an essential role in vascular development.
authors.affiliation: Department of Molecular Biology, NA8.300, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9148, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Diana C
authors.initials: DC
authors.lastname: Chong
authors.forename: Scott A
authors.initials: SA
authors.lastname: Rankin
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Zorn
authors.forename: Ondine
authors.initials: O
authors.lastname: Cleaver
mesh_terms: D000818:Animals; D001483:Base Sequence; D001808:Blood Vessels / Q000196:embryology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D017931:DNA Primers; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D005260:Female; D055785:Gene Knockdown Techniques; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D018919:Neovascularization, Physiologic / Q000235:genetics*; D011247:Pregnancy; D034741:RNA, Small Interfering
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D047908:Intracellular Signaling Peptides and Proteins; D034741:RNA, Small Interfering; C541054:Rasip1 protein, mouse