Fig. 3. Bmp4 signaling promotes cardiogenesis and blocks myogenesis in vitro. (A) RT-PCR analysis of CPM and SpM explants. Explants cultured in the absence (-) or presence (+) of BMP4-conditioned medium. RT-PCR analysis was performed after 3 days. (B) RT-PCR analysis of explants cultured for 3 days in the absence (-) or presence (+) of Noggin protein. BMP4 induced cardiogenesis and blocked skeletal muscle differentiation in CPM explants after 2 and 3 days in culture (n=15/15), while Noggin induced myogenesis in splanchnic mesoderm explants after 3 days in culture (n=7/8).