Immunofluorescence of WT pylorus at (A) E14.5 or (B) E16.5 : (i,vi) DAPI; (ii,vii) SOX9; (iii,viii) NKX2-5; (iv,ix) GATA3; or (v,x) merged. (A–B) NKX2-5 single positive cells are found in the sub-epithelial mesenchyme and ICM (yellow arrowheads in Aviii), while GATA3 single positive cells are present in the pancreatic mesenchyme (white arrowheads in Aix). NKX2-5, GATA3, and SOX9 are co-expressed in the dorsal OLM (asterisks in Av,x and Bv,x). Stomach is left; duodenum is right; and, dorsal is top. Green lines mark the epithelial basement membrane, and white lines separate ICM and OLM. SM = sub-epithelial mesenchyme. Scale bars = 100 μm.