Figure 2

Histological phenotypes of constitutively Dab2 null embryos at E4.5 and E5.5. (A) Fixed and paraffin embedded E4.5 embryos in utero from timed matings of dab2 (+/df) mice were sectioned and stained with H&E to identify implanted embryos. Once found, the serial sections were used for staining with Dab2 to identify dab2 deletion mutants, adjacent sections were then stained with GATA4 and GATA6 as markers for primitive endoderm; and with Oct3/4 to identify cells of the inner cell mass. Consecutive sections of a representative Dab2-positive and a Dab2-negative (dab2 (-/-)) E4.5 embryo are shown. (B) Examples of one wildtype (WT) and five Dab2-negative (dab2 (-/-)) E5.5 embryos are shown. Dab2 staining was used to identify mutant embryos. An adjacent section was stained for GATA4 to identify the endoderm cells. The images shown were sections at or near midline (widest area) of the embryos. A spectrum of severity in disorganization of endoderm cells was seen in the dab2 null embryos. The arrow indicates a parietal endoderm cell in the wildtype.