Syx, a novel Rho A guanine exchange factor, is essential for angiogenesis in vivo

• Published in: The FASEB journal 2008-04, Vol.22 (S2), p.34-34
• Main Authors: Garnaas, Maija, Liu, Miao‐liang, Marx, Ruth, Li, Keguo, Baraban, Jay, Horowitz, Arie, Ramchandran, Ramani
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.22.2_supplement.34

Rho GTPases play an important and versatile role in several biological processes. In this study, we identified the zebrafish ortholog of the mammalian Rho A guanine exchange factor (GEF), Synectin‐binding GEF (Syx), and determined its in vivo function in zebrafish and mouse. syx is expressed specifically in the vasculature of the zebrafish and mouse embryo. Loss‐of‐function studies in zebrafish and mouse point to a specific role for Syx in angiogenic sprouting in the developing vascular bed. Importantly, vasculogenesis and angioblast differentiation steps are unaffected in syx morpholino knockdown embryos, and zebrafish vascular sprouting defects are rescued by orthologous mouse mRNA. We have also uncovered a potential mechanism of endothelial sprout guidance in which Angiomotin (Amot), a component of endothelial cell junctions, plays a synergistic role with Syx during vascular development. These results identify Syx as an essential and vascular‐specific contributor to angiogenesis in vivo. Research Support: Children's Research Institute (Medical College of Wisconsin) Start‐up Funds