Fig. 7. Mutations in the AP-2 binding domain of arrestin cause slow retinal degeneration. All panels show cross sections (0.5 µm) of Drosophila retinas from (A) wild-type, (B) arr2⁵, (C) arr2^K391A and (D) arr2^R393A flies. Dark-reared flies were treated for 30 days of 12 hours light/12 hours dark, then fixed and embedded as described in Materials and Methods.