Fig. 9. Effect of inhibition of Hh signaling in COUP-TFII expression. (A,B) Developing stomachs were dissected from E12.5 Shh wild-type and null mutant, and expression of COUP-TFII mRNA was detected by whole-mount in situ hybridization. Caudal margins of COUP-TFII expression are indicated by dots, and presumptive anatomical boundaries between stomach and duodenum are indicated by arrowheads. The relative size of fore-stomach is indicated by a white line at the top of the stomach. (C-F) Foregut explants were dissected from E10.5 knock-in embryos and cultured for 48 hours in increasing concentrations of cyclopamine (0-10 µM, D-F). Strong lacZ expression was detected in the mesenchyme between lung bud and fore-stomach, as indicated by arrowhead, and cyclopamine inhibited lacZ expression in a dose-dependent manner. Scale bars: in B, 0.5 mm for A,B; in F, 0.5 mm for C-F. oe, esophagus; fs, fore-stomach; hs, hind-stomach; dmg, dorsalmesogastrium; lb, lung bud; St, stomach; Py, pylorus; d, duodenum; e, hind-stomach epithelium.