Fig. 7. Smo^–/– embryoid bodies resemble Ihh^–/– embryoid bodies. PECAM is expressed in endothelial cells lining the interior of the blood island and in core patches in day 13 Ihh and Smo heterozygous embryoid bodies (A,C). Like Ihh^–/– embryoid bodies, the majority of Smo^–/– embryoid bodies fail to cavitate and do not express PECAM in cell-free pockets, only in core patches (B,D). Scale bar: 200 µm.