Fig. 5. RBO facilitates FM1-43-dye endocytosis in central brain synapses. Dye labeling in cultured neurons from wild type (OR) and rbo^ts after 10 minutes at 37°C. Left panels show lower-magnification fields and Nomarski DIC images; right panels show higher-magnification images of FM1-43-labeled synapses (arrows). (A-D) Shown is the range of loading in wild type with more intense (A) and less intense (B) labeling, and in rbo^ts with more intense (C) and less intense (D) labeling. (E) Rescue of loading in rbo^ts/rbo²; rbo-egfp/rbo-egfp neurons. Scale bars: 10 µm. (F) Quantification of FM1-43 loading. The number of loaded varicosities as a percentage of the total varicosities from DIC images, per 20 µm of axon length. Error bars show mean ± s.e.m. for four independent trials for each genotype. ^***Significance of P<0.001.