Figure 2: RT-PCR analysis of pCPCs in culture. Cells expressed Klf4, GATA4 and GATA6 cardiac transcription factors slightly at the beginning with increased expression after prolonged time in expansion culture. Nanog and c-kit were expressed slightly at 2 weeks and significantly after 6 weeks expansion culture. Nkx2.5 expressed in 2 of the 3 cell lines at 6 weeks expansion culture. None of the cells expressed Oct4 or Myh6. Lane 0 = cells passage 0 at the beginning of the culture. Lanes 1-3 = three different cell lines at 2 weeks under 5% oxygen culture in the expansion medium. Lanes 4-6 = three different cell lines at 6 weeks after culture. Lane 7 = positive control; embryonic stem cells for pluripotent genes (Oct4, Nanog and Klf4) and neonatal heart for the other genes. Lane 8 = negative control; no template.