Figure 6.

Mitochondria are present in axons of klc null, but not in milton null, photoreceptors. Eyes were engineered to derive solely from clones homozygous for either klc^8ex94 or milt⁹². Third instar larvae were dissected and photoreceptor axons were labeled with anti-chaoptin (pink) and mitoGFP expressed selectively in the photoreceptors by ey-GAL4. The bundled photoreceptor axons defasciculated upon innervation of the optic lobe in both controls (A and C) and mutants (B and D). (B) Although klc axons appear disordered, they still contain numerous mitochondria. (D) In contrast, milt axons project into the optic lobe more normally, but almost all of the axons lack mitochondria. A few axons do contain mitochondria, but they are likely to be heterozygous axons that persist at this developmental stage. Bars, 20 μm.