Fig. 6. Cyclopamine treatment blocks Hh signalling in Xenopus. Whole-mount in situ hybridisation on embryos incubated in cyclopamine solution from stage 20 onwards (B,D,F,H,J,L) or control embryos (A,C,E,G,I,K). The probes are indicated for each panel. (C-L) Stage 41 embryos; (A,B) stage 30 embryos. Cyclopamine treatment leads to a strong reduction of Gli1, X-Ptc-1 and X-Ptc-2 expression. Some Gli1 expression remains only in the tailbud (arrowhead in B). Expression of both Gli2 and Gli3 is not affected. Anterior is towards the left. Scale bar: 1.35 mm in A,B; 300 µm in C-L.