Fig. 3

a Representative tangential sections of Drosophila retina stained with hematoxylin and eosin show progressive neuronal loss in Rh1 > Aß and Rh1 > αSyn, but not in Rh1 > Tau. Arrowheads highlight representative ommatidia with < 7 rhabdomeres. Scale bar: 10 μm. See also Additional file 3: Figure S3 for low-power views. b Photoreceptor loss in tangential sections was quantified based on the percentage of ommatidia with a preserved complement of 7 rhabdomeres at each timepoint (2-way ANOVA model F-test, p < 0.001). In 30 day-old animals, only 56 % of ommatidia in retinae from Rh1 > Aß flies had the full complement of 7 rhabdomeres, compared with 92 % in Rh1-GAL4/+ controls (p < 0.001), whereas no significant change was seen in Rh1 > Tau (92 %). Given the severity of tissue loss at 30 days, it was not possible to identify preserved ommatidia in Rh1 > αSyn flies (ND); however, in 10 day-old animals, 89 % of ommatidia were intact, compared to 97 % of controls (p < 0.001), consistent with photoreceptor loss. Approximately 100 ommatidia were examined per 100x field of view for at least 4 animals per genotype. Total number of retinae examined (genotype, n₁, n₁₀, n₃₀): Rh1-Gal4/+, 9, 8, 7; Rh1 > Tau, 7, 7, 10; Rh1 > Aß, 7, 8, 8; Rh1 > αSyn 7, 7, ND. Subsetted t-tests were performed for post-hoc comparisons of control animals with each experimental genotype, considering each timepoint independently, and p-values were adjusted using the Bonferroni method. At Day 1, SEM = 0 for Rh1-Gal4/+, Rh1 > Tau, and Rh1 > Aß. ***, p < 0.001