Figure 4.

dTau is not required for forgetting of olfactory memories, and its abrogation increases protein synthesis levels. A, Flies expressing dTauRNAi within αβ MB neurons under c739-Gal4;TubGal80ts performed at levels similar to the control group when they were trained with a reversed contingency. Both groups expressed considerable memory to the more recent learning event. No significant difference in 3 min memory was observed between the experimental and control groups when using the typical learning protocol. Animals were raised at 18°C and shifted to 30°C for 3 d, while uninduced animals were kept at 18°C for these 3 d and were used as controls. The number of experimental replicates (n) is indicated within the bars. B, To measure protein synthesis levels flies were treated with 600 μm puromycin for 16 h. Representative blots of head lysates from WT, tau^KO, and tau^MI flies probed with either anti-puromycin or anti-syntaxin (Syx). For quantifications, levels of the signal corresponding to molecular weight region 30–125 Da in the mutants were normalized using the Syx loading control and are shown as a ratio of their mean ± SEM values relative to their respective level in WT flies, which is arbitrarily set to 1. Stars indicate significant differences (p < 0.0001) from control (open bars) for tau^KO and tau^MI. C, Representative Western blot of head lysates from flies expressing UAS-dtauRNAi using Elav-Gal4;TubG80^ts and probed with anti-puromycin antibody. Animals were raised at 18°C and shifted to 30°C for 3 d, while uninduced animals (U) were kept at 18°C for these 3 d. The genotype of control animals was Elav-Gal4;TubG80^ts/+. For the quantification, levels of the signal corresponding to molecular weight region 30–125 kDa were normalized using the Syx loading control and are shown as a ratio of their mean ± SEM values relative to their respective level in control flies, which is arbitrarily set to 1. The star indicates significant differences (p = 0.0044) from control (open bar), indicative of increased protein synthesis upon dTau loss. D, Representative Western blot of head lysates from flies expressing UAS-dtauRNAi with Elav-Gal4;TubG80^ts using an anti-dTau antibody. The genotype of control animals was Elav-Gal4;TubG80^ts/+ shifted to 30°C for 3 d. Compared with its levels in control animals, dTau was significantly reduced. For the quantification, tau levels were normalized using the Syx loading control and are shown as a ratio of their mean ± SEM values relative to respective levels in control flies, which was set to 1. The star indicates significant differences from the control indicative of reduced dTau levels (*p < 0.0001).