Fig. 6. The F-actin/microtubule crosslinking activity and Ca²⁺-binding domains of Shot L(A) are required in neurons for sensory axon extension. Sensory neurons and their axons in abdominal hemisegments a1-a7 in filleted stage 16 Drosophila embryos. (A) Wild-type. The PNS neurons in each hemisegment are organized into dorsal (d), lateral (l) and two ventral (v,v') clusters. Neurons in the dorsal and lateral clusters send their axons (arrows) in the intersegmental nerve (ISN) to CNS targets. (B) shot³ null mutant. Sensory axons are rudimentary or absent (arrows). Cell bodies remain at the appropriate positions. (C-G) The indicated transgenes are expressed in neurons in shot³ mutant embryos. (C) Shot L(A) expression restores sensory axons (arrows). (D) Shot L(C)-GFP expression fails to rescue sensory axon extension (arrows). (E) Shot L(A)-GAS2-GFP expression fails to rescue sensory axon extension (arrows). (F) Co-expression of Shot L(C)-GFP and Shot L(A)-GAS2-GFP fails to rescue sensory axon extension (arrows). (G) Shot L(A)-EF-hand-GFP expression fails to rescue sensory axon extension (arrows). Scale bar: 25 µm. Anterior, left; dorsal, top.