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Fig. 1 diwanka mutant embryos display severe motor axon defects. (A) Schematic drawing of a spinal hemisegment showing CaP, MiP and RoP neurons and their axonal projection (lateral view). (B) Cross-section through a 28 hpf embryo stained with the znp-1 antibody. Motor growth cones exit the spinal cord (black arrow) and migrate on the medial surface of the somites to the ventrally located choice point (white arrow) at the horizontal myoseptum. CaP (black arrowhead) axons continue further ventrally (white arrowhead), whereas MiP neurons form a branch to the dorsal somite (white arrowhead). Wild-type (C) and diwanka mutant (D-F) embryos at 23 hpf stained with znp-1 antibody. The common path extends between the lower end of the spinal cord (black line) and the horizontal myoseptum (white line). (C) Wild-type CaP (black arrowhead) and MiP (white arrowhead) axons have completed the common path and extended on their cell-type-specific paths. (D-F) Arrowheads points to diwanka mutant motor axons which failed to exit the spinal cord (D), stalled along the common path (black arrowhead in E), stalled at the distal end of the common path (white arrowhead), or have extended on the cell-type-specific path (F).