Differentiation potential of subcultured cells from Sca-1+-enriched populations into endothelial-like cells in vitro. A. All cell populations were stained for the endothelial cell marker CD31 (red) and DAPI (blue) after induction. Scale bar = 200 μm. B. Expression of the endothelial progenitor gene flk-1 and the endothelial cell specific genes CD31, vWF, and VE-Cadherin was analyzed by RT-PCR. RNA extracted from whole postnatal mouse heart (mH) was used as a positive control.