Fig. 2. Loss of Hh signaling appears to disrupt integrity of the spinal cord. (A-C) Isl-1/2 is shown in red; Lim1/2 is shown in green. (A) Wild-type (WT) expression of Isl-1/2 in DRG neurons (arrowheads) just lateral to ventral motor neuron expression and ventral to Lim-1/2 neuron expression. (B) Large clusters (asterisks) predominantly express Lim in smu mutant embryos. (C) Some neurons in large clusters (asterisks) in dtr mutants express Islet. (D-F) Hu staining is shown in red; zn-5 is shown in green. (D) WT embryos show expression of both Hu (cell bodies) and zn-5 (axons) in motor neurons as well as DRG neurons (arrowheads). (E) In smu mutant embryos, large clusters (asterisks) express Hu but not zn-5. (F) Some neurons in large clusters (asterisks) in dtr mutant embryos express both Hu and zn-5. (G,H) Acetylated tubulin is shown as red. (G) Acetylated tubulin is normally expressed in motor neuron axons as well as DRG axons (arrowheads). (H,I) Large clusters (asterisks) in smu and dtr mutant embryos display acetylated tubulin-positive projections. Both Hu and acetylated tubulin are red in I. (J-L) Confocal images of transverse sections showing pHuC::GFP in green and Isl-1/2 in red. (J) WT expression of HuC and Isl-1/2 in DRG neurons (arrowheads) located lateral to the spinal cord. (K,L) Clusters of Isl-1/2+ and HuC+ cells at the ventrolateral edge of the spinal cord (asterisks) in embryos treated with cyclopamine at 24 hpf.