Fig. 4.

Yap deletion reduces squamous stratification in the developing mouse esophagus. (A) Yap deletion leads to a simplified epithelium with a reduced number of Krt8⁺ cells at different stages of esophageal development. Note a few Krt8⁺ cells (arrows) in E18.5 mutant esophagus and the thickness of Krt8⁺ cells is reduced (n=3). (B,C) Yap deletion reduces squamous differentiation and only a few cells on the top layer of the epithelium (arrows) express Krt13 at E15.5 (B) and E18.5 (C) (n=5). The thickness of Krt13⁺ cells is reduced in Yap KO mutants. Note the apical nonspecific staining of Krt8 and Krt13 in p63⁺ basal cells of E18.5 mutant esophagus. Also note the normal shedding keratin in the middle of the esophageal lumen and that the thickness of Krt13⁺ cells is reduced at E15.5 and E18.5. Data represent mean+s.e.m. (n=5). *P<0.05, ***P<0.001 by unpaired, two-tailed Student's t-test. Scale bars: 20 µm.