Figure 4.

Differentiation of cardiac precursors into functional cardiomyocytes. (A) RT-PCR analysis of cardiac-specific gene expression in NMCs from FGF-2^+/+ or FGF-2^–/– mice maintained in control (C) or differentiation medium (D) in the absence of FGF-2 (None), after 1 week or 3 weeks in culture. (B) Quantification of troponin I⁺ cells and spontaneously contracting cells in culture of differentiated cardiac precursor from FGF-2^+/+ and FGF-2^–/– mice after 3 weeks in control medium (white bars) or differentiation medium (black bars); n = 6–10. *P < 0.05. (C) RT-PCR analysis of cardiac-specific gene expression in NMCs from FGF-2^+/+ or FGF-2^–/– mice maintained in control or differentiation medium in the presence of FGF-2 or FGF-1 after 1 week or 3 weeks in culture.