Whole mount X-gal staining of pylorus from (A) Nkx2-5lacZ/+ or (B) Gata3lacZ/+ mice at (i–ii) E14.5 and (iii) E18.5. (i,iii) Lateral view: stomach is left; duodenum is right; dorsal is top. (ii) Ventral view: stomach is top; duodenum is bottom. (Ai,Bi) Nkx2-5 and Gata3 have similar expression patterns, with extension dorsally into the pancreatic mesenchyme (PM in Aii) and ventrally into the gastric ligaments (black arrowheads in Ai and Bi), however, the width of the Gata3 expression domain is narrower than Nkx2-5. (Aii,Bii) Nkx2-5 expression is completely circumferential (red arrowhead in Aii), while Gata3 expression is discontinuous ventrally (red arrowhead in Bii). (Aiii,Biii) By E18.5, the gastric ligaments have lengthened to reach the esophagus (pancreatic mesenchyme outlined by dashed line in Aiii). Scale bars = 100 μm.