Figure 4: RT-PCR analysis of cardiac genes. pCPCs before treatment with oxytocin (lane 0) expressed GATA4 and Nkx2.5 slightly. None of the cells in expansion medium at day 21 (lane 1) expressed any cardiac transcription factors. After 21 days treatment with oxytocin (lane 2), pCPCs down-regulated GATA4, up-regulated Nkx2.5 and expressed troponin-I. Neonatal heart (lane 3) and no template control (lane 4) were used as positive and negative controls, respectively.