Fig. 1.

Sagittal sections of murine esophagi from E14.5 fetuses show progressive myogenin expression over 7 days of culture: day 0 (A), day 5 (B) and day 7 (C). a Myogenin expression (red nuclear staining) in the diaphragm. b Myogenin expression in 3–4 subpharyngeal nuclei. c Robust myogenin expression in the tongue. d Myogenin expression extending caudally along the rostral muscularis externa layers. e Myogenin expression in the muscularis externa approaching the stomach. Scale bars for large panels = 500 μm; scale bars for insets = 100 μm.