Fig. 6. The ventral spinal cord phenotype of Ptc mutants can be partially rescued by removing Gli2 function. In Ptc mutants that survive to E9.5, ventral spinal cord markers expand dorsally (A-D) compared with wild-type embryos a day later at E10.5 (E-H). Insert in A is a more anterior spinal cord section. In Ptc;Gli2 double homozygous mutants, Shh expression is lost in the spinal cord (I), Nkx2-2 expression is greatly reduced in the ventral midline (J), and the expansion of Isl1/2 and Pax6 seen in Ptc^–/– mutants are shifted more ventrally (K,L). White arrowhead indicates ventral limit of Pax6 domain. Scale bar: 78 µm in A-D; 100 µm in E-L.