Pluripotency marker expression in P19 EC and TNGA ES cells. (A) RT-PCR data showing that cultured undifferentiated P19 cells express a set of pluripotency genes (Nanog, Oct4, Rex1, Sox2) that are also characteristic of the undifferentiated ES cells. RNA was extracted from P19OTOY cells and gene expression analysed using a two-step semiquantitative RT-PCR reaction (for details, see Materials and Methods). The expression levels of pluripotency markers are shown. Expression of GAPDH (cycle 28), GFP (cycle 32), Nanog (cycle 36), Oct4 (cycle 32), Rex1 (cycle 40), and Sox2 (cycle 32) were detected. (B) Correlation of Nanog expression and Nanog-GFP expression in TNGA ES cells. HN and LN cells were sorted and stained for Nanog expression (red). Although there is some expression of Nanog in the LN population, it is more heterogeneous and lower than in the HN population. The green channel shows the Nanog-GFP reporter, and the blue channel shows DAPI staining. (0.75 MB TIF)