Fig. 6. Marker gene analyses confirm morphological changes in the conditional mutant stomach. (A,B) E16.5 sagittal sections were stained for stratified epithelial cell marker CK14. Intense staining was found in the basal cells in the control (A), while only faint staining was observed in the anterior edge of fore-stomach of the COUP-TFII conditional mutant (B). (C,D) Whole E11.5 embryos were cross-sectioned and Shh expressions in the fore-stomach were examined by section in situ hybridization using ³⁵S-UTP labeled probes. Positive signals were pseudo-colored (red) and overlaid on bright-field image of Hematoxylin staining. (E-G) Paraffin sections of E18.5 stomachs were stained with anti-CK14 antibody. CK14 staining (dark brown) remained as intense throughout the fore-stomach of the control (E) and mutant (F). Again, it was barely detectable in the more caudal regions of the stomach of the mutant (G) in comparison with similar anatomical position of fore-stomach of the control (E).