Fig. 5. IFT88 is essential for Hh signaling in the spinal cord. (A) Pax7 is expressed in the dorsal neural progenitors in the spinal cord in normal embryos. (B) Pax7 is expressed in the entire spinal cord, except for the most dorsal part in Shh mutants. (C) Pax7 expression remains dorsally restricted in Ift88^null mutant (C) and in Shh/Ift88^null double mutant (D) spinal cord. (E) Pax6 is weakly expressed in the dorsal spinal cord and strongly expressed in the intermediate region in wild-type embryos. (F) Strong Pax6 expression is shifted to the ventral most region of the spinal cord in Shh mutants. (G) Strong Pax6 expression is expanded to the ventral region of the spinal cord in Ift88^null. It also appears to be expanded more dorsally. (H) Strong Pax6 expression appears to be expanded both dorsally and ventrally in Shh/Ift88^null double mutants. (I) Lhx3 is expressed in differentiated motoneurons and V2 interneurons in normal embryos. (J) No or few Lhx3-expressing cells are present in ventral midline of Shh mutant spinal cord. (K,L) Lhx3 expression is expanded to the ventral midline of the spinal cord in Ift88^null (K) and Shh/Ift88^null double mutants (L). (M) En1-expressing V1 interneurons are dorsally adjacent to V2 interneurons in normal embryos. (N) There are no or very few En1-expressing cells present in the ventral midline of the Shh mutant spinal cord. (O,P) En1 expression is expanded to the ventral midline of the spinal cord in both Ift88^null (O) and Shh/Ift88^null mutant (P) embryos. Broken yellow lines outline the spinal cord. Arrowheads in A,C,D indicate the ventral border of the Pax7 expression domains. Arrowheads in E-H indicate the boundary between the dorsal weak Pax6 domain and the strong Pax6 domains. Arrowhead in I,K,L and M,O,P indicate the ventral border of the expression domains of Lhx3 and En1, respectively.