Fig. 3. Whole-mount in situ hybridization showing the localization of Ptc-1 (AâC,S,V,X), Ptc-2 (DâF,T,W,Y), Shh (GâI,U,Z), Gli-1 (JâL), Gli-2 (MâO) and Gli-3 (PâR). (A,D,G,J,M,P) Dorsal views at stages 14. (B,E,H,K,N,Q) Lateral views at stage 26. (C,F,I,L,O,R) Lateral views at stage 31. (SâU) Lateral views of facial regions at stage 31. (V, W) Transverse sections at stage 14. (XâZ) Transverse sections through spinal cord and notochord at stage 27. Embryos in (B,C,E,F,H,I,K,L,N,O,QâU) were cleared by benzyl alcohol-benzyl benzoate.