Fig. 1. Klf5 expression in ESCs. (A,B) Klf5 mRNA (A) and protein (B) levels decrease soon after the induction of ESC differentiation. ESCs were differentiated as embryoid bodies (EBs) or in monolayer. (C) Klf5 is highly expressed in undifferentiated ESCs and colocalised with Oct3/4 and Nanog. Scale bars: 50 µm. (D) RT-PCR of Klf5 in ESCs, and in E3.5 and E6.5 embryos. (E) Klf5 is expressed in morulae together with Oct3/4 and Nanog. (F,G) E3.5 embryos express Klf5, Oct3/4 and Nanog in the inner cell mass. Scale bars: 20 µm. (H) Two consecutive sections of an E11.5 embryo were stained with anti-Klf5 and -Oct3/4 antibodies. The arrowheads indicate the groups of cells in the genital ridge (primordial germ cells) expressing both Klf5 and Oct3/4. The arrow indicates the stomach epithelium, where Klf5 is also expressed (Ohnishi et al., 2000).