Fig. 6. The effects of inhibiting Wnt signaling on expression of dorsal tube-specific genes. (A,B,D-F) Whole-mount in situ hybridization following electroporation with (A) control GFP or (B,D-F) dNLEF1 to the left hemi-tubes and 10 hours reincubation. While the control vector had no effect on bilateral transcription of Cad6B (A), Pax3, Msx1 or RhoB (not shown), there was unilateral downregulation of Cad6B, Pax3 and Msx1, but not of RhoB in dNLEF1-treated hemi-tubes (transfected areas depicted between arrows). Results were confirmed by transverse section analysis. (C) Transverse section of an embryo that received Xdd1-GFP and was analyzed for expression of Cad6B in combination with GFP immunostaining. Downregulation of Cad6B (blue) in dorsal hemi-tube expressing Xdd1-GFP (brown). NC cells emigrating from the treated side are devoid of Xdd1-GFP. (G,H) Transverse sections following electroporation with dNLEF1 to show bilaterally symmetrical expression of Sox9 and Foxd3. The hemi-tubes in the transfected sides are slightly narrower (^*). Similar results were obtained for all tested genes (RhoB, Sox9, Cad6B, Msx1, Pax3 and Foxd3) upon transfection with ß-catenin/engrailed or Xdd1 (not shown). (I) High magnification of the dorsal hemi-tube of an embryo electroporated with Xdd1-GFP to show that individual cells expressing Sox9mRNA (upper panel) co-express GFP (middle panel). The lower panel is an overlay of the upper two. EC, ectoderm; NT, neural tube. Scale bar: 40 µm in C,G,H; 20 µm in I.