Figure 5. Intestinal molecular regionalization occurs by E10.5 and can be affected by Wnt and Cdx2 concentration.

(A) Wholemount image of E14.5 gut with the different anterior-posterior divisions dissected for microarray analysis labeled. Distinction between anterior and posterior small intestine was chosen as the midpoint of the small intestine. (B–F) Wholemount in situ hybridization (B, D, E) or immunofluorescence (C, F) images of E10.5 embryos (B–C) or E14.5 gut (D–F) showing expression of posterior small intestine-specific Osr2 (B, E), large intestine-specific Ly6a (C, F), and anterior small intestine-specific Tm4sf4 (D). Green arrows refer to the anterior border of the intestinal staining and red arrows refer to the posterior border of the intestinal staining. (G–J) Wholemount confocal immunofluorescence images of E8.25 foreguts cultured for 24 hours before fixation and stained for Ly6a (white in G, I, green in H, J) and Foxa2 (red in H, J). Foreguts were treated with soluble GSK3iXV at 10 nM (G–H) or 1 µM (I–J). (K–M) Immunofluorescence images of inducible Cdx2 ES-derived endoderm treated with 10 nM GSK3iXV (K), 1 µM GSK3iXV (L), 1 µg/mL Doxycycline (M), or 50 nM GSK3iXV and 1 µg/mL Doxycycline (N) for 24 hours before fixation and stained for Ly6a. Scale bar equals 50 µm in H, J, K–N.