Kinetics of appearance of 4-integrin⁺cells in the culture initiated from ES cell-derived FLK1⁺cells. FLK1⁺ cells sorted from differentiating CCE cells were cultured in a gelatin-coated dish for 1 to 3 days and analyzed for expression of VE-cadherin and 4-integrin by flow cytometry. CD45⁺ cells and TER119⁺ cells were excluded from the analyses. The numbers indicate the percentage of cells that appeared in each quadrant. The result shown is a representative of three independent experiments.