Figure 1. Reduced DNA synthesis in hES cells is linked to loss of pluripotency.

(A) Experimental design. (B) Immunofluorescence microscopy detection of Oct4 and BrdU in asynchronous human ES cells (WA09/H9) at 24 h, 48 h, and 72 h and cultured in differentiating medium under feeder-free conditions (scale bar = 200 μm). (C) Quantitation of results depicted in (B); the error-bars represent the standard error of the mean (SEM) for four independent determinations of 400 each (n=1600). Changes in Oct4 and BrdU signals between 48h and 72 h are statistically significant (P<0.05) (D) Micrographs of nuclei at higher magnification show changes in nuclear morphology after 24 h 48 h, and 72 h under differentiating conditions (scale bar = 20 μm).