Fig. 3. The type D motoneuron axon guidance defects in unc-71 mutants. (A-J) Axonal morphology of the type D neurons visualized by juIs76[Punc-25GFP] marker. (A,B) Low magnification of wild-type (A) and unc-71 (B) animals. unc-71 animals have axonal gaps in the dorsal cord (arrows). (C,D) L1 larvae of wild type (C) and unc-71 (D) animals. Arrows show DD₂ and DD₅ commissures, which did not grow out in unc-71 animals. (E,F) Ventral views of wild-type (E) and unc-71 (F) animals. In wild-type animals, DD and VD ventral processes form a tight bundle (arrow in E); in unc-71 animals, defasciculation is seen as two separated bundles (arrow in F). (G,H) Dorsal views of wild-type (G) and unc-71 (H) animals. (G) All commissures (arrowhead) reach the dorsal cord (arrow) from the same side in wild-type animals. (H) In unc-71 animals, commissures (arrowheads) reach the dorsal cord (arrow) from both sides (left side, narrow arrowhead; right side, arrowhead) and some do not reach the dorsal cord (asterisk). (I,J) Ventral view of wild-type and unc-71 animals expressing nuIs25[Pglr-1GFP] in the interneurons. In wild-type animals, the ventral cord processes of these interneurons form a tight bundle (arrow in I); in unc-71 they are defasciculated (arrow in J). (K,L) Schematics of VD₁₃ neuron morphology viewed using juIs76 marker (K) and AWC neuron morphology viewed by kyIs136[Pstr-2GFP] marker (L) in wild-type and unc-71 animals. Numbers represent the percentage of particular phenotypes. Scale bars: 20 µm in C,D; 50 µm in A,B,E-J.