Fig. 2. Abnormal morphology and loss of epiblast after implantation. (A) One litter of embryos at 3.5 dpc was stained for Oct4 expression (green). Genotypes for each embryo are indicated in the middle panel. (B) Embryos at 4.5 dpc were stained with anti-Oct4, anti-Nanog and anti-Gata4 antibodies. Images taken with independent wavelength were coloured in green for Oct4 and Nanog, red for Gata4. Note Gata4-positive primitive endoderm cells maintain Oct4 protein (yellow cells, middle panels) at this stage in both heterozygous and homozygous null embryos. (C) Mbd3^+/- and Mbd3^-/- embryos at indicated stages shown in phase contrast (top panels of each set) or stained for Oct4 (green; bottom panels of each set). Asterisks indicate non-specific staining at ectoplacental cone.