Figure 5
FGF and BMP signaling induce vascular endothelial cell and cardiomyocyte differentiation, respectively, in amniogenic somatopleure explants. (a–e) Amniogenic somatopleure explants from quail embryos at 9ss to 11ss are cultured in the presence of FGF2 (10 ng/ml) (n = 13) (b), BMP4 (300 ng/ml) (n = 14) (c) or both (n = 12) (d,e) and immunostained for the cardiomyocyte marker cardiac troponin I (TnI) and quail-specific vascular endothelial cell marker QH1. Control explants (n = 11) show staining for neither marker (a). Stimulation with FGF2 or BMP4 induces differentiation of quail somatopleural cells into vascular endothelial cells and cardiomyocytes, respectively (b,c). Simultaneous stimulation with FGF2 and BMP4 results in only vascular endothelial differentiation (d) or differentiation into both endothelial cells and cardiomyocytes (e) in 8 and 4 of 12 explants, respectively. TO-PRO-3 is used to counterstain nuclei. (f) Summary of the effects of FGF and BMP signaling on somatopleural cell differentiation. Scale bars, 15 µm for (a,c) and 40 µm for (b,d,e).
