Induction of endothelial cell growth by angiopoietin-1. Two thousand TEK⁺ cells from the AGM region were seeded onto OP9 cell layers in a 24-well plate. When angiopoietin-1 was added, cord-like strutures of endothelial cell growth were observed (A) and these cells show uptake of DiI-Ac-LDL (B).