Fig. 3

Pax7 ^−/− mice display defective proximal-to-distal progression of ME development. a–d Longitudinal sections of P0 and P7 Pax7 ^+/− and Pax7 ^−/− esophagi were stained with antibodies to αSMA, SA, and DAPI. Pax7 ^−/− esophagi have an aberrantly proximally located skeletal-smooth muscle boundary (arrows). The SA⁺ tissue near the distal end of the Pax7 ^+/− esophagus in (a) is the diaphragm. e The distance between the distal-most SA⁺ cell and the LES was measured and is represented by the red portion of the histogram bars. The distance decreases progressively with age in Pax7 ^+/− esophagi, but this fails to occur in Pax7 ^−/− esophagi. Values are means ± SD, n = 3–5. Bars: 1 mm. ***P < 0.001