Deletion of endogenous Tau proteins is not detrimental in Drosophila

Abstract

Human Tau (hTau) is a highly soluble and natively unfolded protein that binds to microtubules within neurons. Its dysfunction and aggregation into insoluble paired helical filaments is involved in the pathogenesis of Alzheimer’s disease (AD), constituting, together with accumulated β-amyloid (Aβ) peptides, a hallmark of the disease. Deciphering both the loss-of-function and toxic gain-of-function of hTau proteins is crucial to further understand the mechanisms leading to neurodegeneration in AD. As the fruit fly Drosophila melanogaster expresses Tau proteins (dTau) that are homologous to hTau, we aimed to better comprehend dTau functions by generating a specific tau knock-out (KO) fly line using homologous recombination. We observed that the specific removal of endogenous dTau proteins did not lead to overt, macroscopic phenotypes in flies. Indeed, survival, climbing ability and neuronal function were unchanged in tau KO flies. In addition, we did not find any overt positive or negative effect of dTau removal on human Aβ-induced toxicity. Altogether, our results indicate that the absence of dTau proteins has no major functional impact on flies, and suggests that our tau KO strain is a relevant model to further investigate the role of dTau proteins in vivo, thereby giving additional insights into hTau functions.

Disease-Associated Mutant Tau Prevents Circadian Changes in the Cytoskeleton of Central Pacemaker Neurons

“…This is supported by the recent finding that the loss of dTau reduces sleep and increases activity (Arnes et al, 2019). Furthermore, we found that also haploinsufficiency by using a dTau knock-out-line (Burnouf et al, 2016), impaired the sleep pattern (Supplementary Figure S3C) and induced hyperactivity when tested at 5-day ( Supplementary Figure S3D). However, hTau V337M was significantly worse than hTau WT , showing that the mutation does impair the function of Tau in regulating sleep.…”

DrosophilaTau Negatively Regulates Translation and Olfactory Long-Term Memory, But Facilitates Footshock Habituation and Cytoskeletal Homeostasis

“…Drosophila tau (dTau) is expressed in the developing and adult CNS, prominently in photoreceptors (Heidary and Fortini, 2001), cell bodies, and neuropils of the visual system and the central brain (Bolkan and Kretzschmar, 2014). Functional regulation by phosphorylation seems conserved in flies, since dTau possesses multiple SKXGS motifs and has been shown to be phosphorylated (Doerflinger et al, 2003;Burnouf et al, 2016). Examination of its physiological functions was attempted with the generation of a knock-out (tau KO ) mutant lacking exons 2-6 including the tubulin-binding repeats (Burnouf et al, 2016).…”

“…Functional regulation by phosphorylation seems conserved in flies, since dTau possesses multiple SKXGS motifs and has been shown to be phosphorylated (Doerflinger et al, 2003;Burnouf et al, 2016). Examination of its physiological functions was attempted with the generation of a knock-out (tau KO ) mutant lacking exons 2-6 including the tubulin-binding repeats (Burnouf et al, 2016). However, obvious phenotypes were not reported for these mutants, and apparently this was not a consequence of the upregulation of other microtubule-associated proteins, as in mice (Harada et al, 1994), furthering the notion that dTau may not be an ortholog of the vertebrate protein.…”

NORMA-The network makeup artist: a web tool for network annotation visualization

“…Null-Tau mutants in Drosophila were used to demonstrate broad changes in their brain proteome with mass-spectrometry. To briefly describe the protocol used in this study, tauKO mutant flies [46] and Cantonised-w1118 control flies were cultured on standard wheat-flour-sugar food supplemented with soy flour and CaCl2, at 25°C in 50-70% relative humidity in a 12 h light/dark cycle. Three to four biological and two technical replicas from each genotype were used with each biological replica counting 10 brains.…”