Fig. 3

Impact of Porcn activity during axial elongation. Embryos were cultured for 24h (E8.5 to E9.5) in the presence or absence of the Porcn inhibitor, IWP-01. Whole-mount in situ hybridization with Crabp1 (A-B), Msgn1 (C-D), Cdx2 (E–F), Tbxt (G-H’), Uncx4.1 & Tbx5 (I-J), Sox2 (K-L) and Shh (M–N) probes. G’, H’, K’ and L’ show dorsal views of the posterior end of the respective embryos. I’, J’, K’’, L’’, M’ and N’ show transverse sections at the axial levels indicated by the dashed lines in the respective embryos. Arrows and arrowheads in A and B indicate first and second branchial arches, respectively. Tbxt expression in the caudal region is reduced to a small spot (arrows in H and H’). Arrows and arrowheads in I’ and J’ indicate paraxial mesoderm and neural tube, respectively. The neural tube (arrows in K’’ and L’’) becomes a flat structure in the posterior end of the IWP-01-treated embryo. Arrows and arrowheads in M’ and N’ emphasize Shh expression in the notochord and gut, respectively