Fig. 5. Membrane cycle of enlarged synaptic vesicles induced by Rab5N142I. (A-C) Cross sections of photoreceptor nerve terminals indicate the exo- and endocycle of synaptic vesicles in the shi¹;;Rh1-GAL4 UAS-Rab5N142I/+ double mutant. After keeping the mutant flies at 20°C (A), they were put at 30°C for 1 minute under light illumination (B) followed by the incubation at 20°C for 30 minutes (C). Scale bar, 500 nm. (D) Changes in the diameter of the R1-6 photoreceptor nerve terminals of shi¹ (open bars) and shi¹;;Rh1-GAL4 UAS-Rab5N142I/+ (shaded bars) mutants caused by the above temperature shift.