Whole-mount Fly Eye and Brain Imaging

All flies were age-matched for experiments. The whole-mount preparation of fly eyes and brains was performed as previously described^{46 (link)}.The following primary antibodies were used with the indicated dilutions: anti-lamin B1 (Sigma, 1:20), anti-GABA (GeneTex, 1:200), anti-human pan-tau (Dako, 1:200), anti-tau-C3 (Invitrogen, 1:200), anti-GFP (Abcam, 1:100), anti-AT8 (Thermo, 1:200), anti-AT100 (Thermo, 1:100), and anti-PHF1 (Abcam, 1:100). Alexa Fluor 488, Cy3, and Cy5 conjugated secondary antibodies (Jackson ImmunoResearch Laboratories) were used at 1:100 dilutions. F-Actin enriched rhabdomere and spots of aberrant actin accumulations were labeled by rhodamine-conjugated phalloidin (Sigma, 1:20) and Alexa Fluor 633-conjugated phalloidin (Thermo, 1:50), respectively. Samples were analyzed on Zeiss LSM510 or LSM800 confocal microscopes.