Fig. 4. Analysis of AP patterning defects in conditional COUP-TFII mutant stomach. Controls and conditional mutant embryos were obtained by mating with COUP-TFII floxed homozygous males and Nkx3-2^Cre/+; COUP-TFII^flox/+ females as described in Fig. 3. (A,B) Stomachs were dissected from E16.5 embryos and examined in whole mount under the dissecting microscope. The presumptive margin between fore-stomach and hind-stomach is indicated by dots and is shifted slightly anteriorly in the mutant. (C,D) Whole-mount postnatal day 28 stomachs were dissected and examined under the dissecting microscope. Position of limiting ridge is indicated by arrowhead. A clear anterior shift of the limited ridge is observed in the conditional mutant. (E,F) Dissected stomachs from E16.5 embryos were longitudinally sectioned and stained with Hematoxylin and Eosin. (G-H) Higher magnification of similar regions as indicated by lines in E,F. e, epithelium; sm, smooth muscle layer; fs, fore-stomach; hs, hind-stomach; oe, esophagus; d, duodenum.