Figure 3

Role of EGFL7 in lumen formation. (a) During primitive plexus formation angioblasts assemble into vascular cords which are subsequently transformed into vascular tubes. Cord-to-tube transition is characterized by cell polarization, redistribution of junctional proteins and eventually, changes in cell shape. EGFL7 is secreted by endothelial cells into the extracellular matrix, where it affects the process of lumen formation. (b) In the absence of EGFL7 angioblasts fail to separate, which leads to the formation of vessels lacking a vascular lumen.