Figure 5

β-gal⁺ cells in E10.5 and E12.5 GI mesenchyme. Littermate DβH-nLacZ⁺ whole-mount embryos were stained for β-galactosidase and GI tissues were dissected out and photographed as described in Methods. Panels A-H show dissected GI tracts (panels A and E; left = anterior, right = posterior) and end-on views of the cross-sections (panels B-D, F-H) at the indicated places (red arrowheads). The leftmost cross-sections (panels B and F) are at the level of the nascent stomach. In the DβH-nLacZ⁺ Hlx^+/+ (not shown) or Hlx^+/- embryos (panels A-D), blue β-gal⁺ cells are present along the length of the GI mesenchyme within the ventral wall. However, in the DβH-nLacZ⁺ Hlx^-/- embryos (panels E-H), β-gal⁺ cells are present anteriorly but not posteriorly. White bars, 200 μm. Panels I and J show β-gal⁺ cells in E12.5 GI mesenchyme. The locations of the stomach (Stom), small intestine (SI), and liver (L) in the preparations are indicated. In the DβH-nLacZ⁺ Hlx^+/+ embryos (panel I), blue β-gal⁺ cells are evenly distributed within and along the length of the gut mesenchyme. However, in the DβH-nLacZ⁺ Hlx^-/- embryos (panel J), there is a concentration of β-gal⁺ cells in the lateral wall of the gastric mesenchyme, and only scattered β-gal⁺ cells are seen more distally in the GI tract (beyond the dotted red bar). Black bars, 500 μm.