Figure 3.

Methylene blue prevents insoluble hTau^0N4R aggregate formation at a specific concentration. A, B, Survival curves of untreated and treated with different concentrations of MetBlu driver heterozygote control (A) and animals accumulating pan-neuronally hTau^0N4R at 30°C (B). The data represent the mean ± SEM from two independent experiments with at least 300 flies assessed per genotype. Right, The different concentrations of MetBlu. The dotted lines indicate the 50% attrition levels. Statistical details are provided in Table 1 and 2. C, D, Representative Western blots of soluble (C) and insoluble (D) fractions generated from adult flies untreated or treated with different concentrations of MetBlu probed with 5A6 anti-Tau antibody. hTau^0N4R was either expressed for 12 d (ON) or is repressed for 10 d following 12 d of expression (OFF). To determine the effect of the drug on hTau^0N4R insoluble aggregate formation, flies were shifted onto food containing MetBlu ranging from 50 to 1000 μm at 18°C to silence the transgene for 10 d (OFF). The different concentrations of MetBlu used are indicated above each bar. The level of Syx was used as control for quantifications. The normalized level of hTau^0N4R (OFF condition, untreated) for each quantification was fixed to one. Error bars indicate mean ± SEM relative to respective levels in flies that exist under transgene transcriptional silencing conditions. The star indicates significant differences from the control genotype; n ≥ 5 for C and n ≥ 6 independent blots for D.