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Fig. 1 | Skeletal Muscle

Fig. 1

From: PAX7 is required for patterning the esophageal musculature

Fig. 1

Pax7 −/− mice have megaesophagus. a, b P21 Pax7 +/− and Pax7 −/− esophagi. cj Longitudinal sections of P21 Pax7 +/− and Pax7 −/− esophagi were stained with antibodies to α-smooth muscle actin (αSMA; red) and sarcomeric actin (SA; green) for smooth and skeletal muscles, respectively. c, d Pax7 −/− esophagi have an aberrantly proximally located skeletal-smooth muscle boundary (arrows). Note that the Pax7 +/+ esophagus is cut off at the top end, making it appear shorter than the Pax7 −/− esophagus, the full length of which is shown. In fact, at P21, Pax7 −/− esophagi are shorter than Pax7 +/+ esophagi (see Fig. 3e). e, f The proximal ME of Pax7 −/− esophagi has skeletal muscle of relatively normal appearance. g, h Smooth muscle cells are dispersed with skeletal myofibers around the skeletal-smooth muscle boundary (Boundary). Note that the ME of the Pax7 −/− esophagus is thinner than the control at the skeletal-smooth muscle boundary. i, j The distal Pax7 −/− esophagus has a long, thin extension of smooth muscle instead of the short, broad segment of smooth muscle found in controls. ej The thin αSMA+ layer adjacent to the ME is the muscularis mucosa (arrowheads). k, l Longitudinal sections through the LES of P21 Pax7 +/+ and Pax7 −/− esophagi mice were stained with antibodies to αSMA (green) and nNOS (red) to label inhibitory intramural neurons. m Quantification of the relative numbers of nNOS+ cells to αSMA staining in the ME of the LES. Values are means ± SD, n = 5. Bars: (c, d) 1 mm; (el) 0.2 mm

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