title: RhoJ is an endothelial cell-restricted Rho GTPase that mediates vascular morphogenesis and is regulated by the transcription factor ERG.
abstract: ERG is a member of the ETS transcription factor family that is highly enriched in endothelial cells (ECs). To further define the role of ERG in regulating EC function, we evaluated the effect of ERG knock-down on EC lumen formation in 3D collagen matrices. Blockade of ERG using siRNA completely interferes with EC lumen formation. Quantitative PCR (QPCR) was used to identify potential downstream gene targets of ERG. In particular, we identified RhoJ as the Rho GTPase family member that is closely related to Cdc42 as a target of ERG. Knockdown of ERG expression in ECs led to a 75% reduction in the expression of RhoJ. Chromatin immunoprecipitation and transactivation studies demonstrated that ERG could bind to functional sites in the proximal promoter of the RhoJ gene. Knock-down of RhoJ similarly resulted in a marked reduction in the ability of ECs to form lumens. Suppression of either ERG or RhoJ during EC lumen formation was associated with a marked increase in RhoA activation and a decrease in Rac1 and Cdc42 activation and their downstream effectors. Finally, in contrast to other Rho GTPases, RhoJ exhibits a highly EC-restricted expression pattern in several different tissues, including the brain, heart, lung, and liver.
authors.affiliation: Division of Cardiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Yuan
authors.forename: Anastasia
authors.initials: A
authors.lastname: Sacharidou
authors.forename: Amber N
authors.initials: AN
authors.lastname: Stratman
authors.forename: Alexandra
authors.initials: A
authors.lastname: Le Bras
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Zwiers
authors.forename: Katherine
authors.initials: K
authors.lastname: Spokes
authors.forename: Manoj
authors.initials: M
authors.lastname: Bhasin
authors.forename: Shou-Ching
authors.initials: SC
authors.lastname: Shih
authors.forename: Janice A
authors.initials: JA
authors.lastname: Nagy
authors.forename: Grietje
authors.initials: G
authors.lastname: Molema
authors.forename: William C
authors.initials: WC
authors.lastname: Aird
authors.forename: George E
authors.initials: GE
authors.lastname: Davis
authors.forename: Peter
authors.initials: P
authors.lastname: Oettgen
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000254:growth & development*; D015153:Blotting, Western; D042783:Endothelial Cells / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D047468:Immunoprecipitation; D007834:Lasers; D051379:Mice; D008819:Mice, Nude; D042282:Microdissection; D009024:Morphogenesis; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D015534:Trans-Activators / Q000378:metabolism*; D000071230:Transcriptional Regulator ERG; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
chemical_list: C072312:ERG protein, human; D034741:RNA, Small Interfering; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; C417188:RHOJ protein, human; D020741:rho GTP-Binding Proteins