Cluap1KOembryos have defects in floorplate induction. (A,C,E) Cluap1WT E9.5 embryos stained for Arl13b (green) show cilia in the neural tube and surrounding tissue. Staining for Sonic hedgehog ligand (red) shows a Shh immunopositive floorplate. (B,D,F) Cluap1KO embryos show an absence of cilia as indicated by the lack of Arl13b staining. Note the lack of a clearly defined Shh immunopositive floorplate. Hoechst nuclear stain in blue. Scale bars are 21 μm.