Fig. 3

Different pluripotent states have distinct expression profiles. a. Schematic diagram illustrating the change in relative protein expression levels of the pluripotency-associated genes, NANOG, KLF4 and OCT4 during the transition from a naïve to a primed state of pluripotency. KLF4 is lost as cells exit the naïve state of pluripotency, NANOG is transiently downregulated and OCT4 is maintained at similar levels throughout this period. b. Schematic diagram showing the expression domains of NANOG, KLF4 and OCT4 from embryonic day (E) 3.5 to 7.5 of development. NANOG, KLF4 and OCT4 are all expressed within the ICM of the early blastocyst. While OCT4 is relatively homogeneous, KLF4 and NANOG are both heterogeneously expressed. At E4.5, the epiblast (Epi) homogeneously expresses all 3 of these markers, while the primitive endoderm expresses low levels of OCT4 and KLF4 but not NANOG. At early implantation (E5.5), KLF4 expression is lost and OCT4 and NANOG are coexpressed throughout the Epi. By E6.5–7.5, OCT4 continues to be expressed throughout the Epi while NANOG is restricted to the posterior Epi. c. Representative confocal optical sections of ESC, EpiLC and EpiSC cultures. All cell lines were derived from the 129/Ola E14 parental ESC line. ESCs were maintained in serum and LIF and expressed OCT4, NANOG and KLF4 heterogeneously. EpiLCs expressed OCT4, but downregulated NANOG, and lost KLF4 expression. EpiSCs (derived by culture of E14 ESCs in FGF and Activin for >20 passages) expressed high levels of NANOG and OCT4, but no KLF4