Fig. 1

Overexpression of human and zebrafish tau proteins in zebrafish embryo resulted in neuronal death. a Schematic diagrams of each expression construct containing either wild-type or truncated forms of human and zebrafish Tau tagged with green fluorescence protein (GFP). Each expression construct was driven by the HuC promoter. The black bar represents one repeat of tubulin binding domain. The wild-type human and zebrafish tau proteins contain four and three repeats, respectively. b Each expression construct was microinjected into zebrafish embryos at the one-cell stage. Zebrafish embryos with GFP signals at 24 to 48 hpf were selected for image analysis. Embryos are shown in the lateral view with the anterior to the left and dorsal to the top. The boxed region of each panel (a-g) is enlarged (a′-g′′) to show the GFP-labeled neuronal cells in 24 to 48 hpf embryos from the lateral view. Scale bars: 100 µm. c The five GFP-labeled neuronal cells in embryos injected with pHuC-h4R-tau-GFP were traced with the aid of time-lapse recording. Puncta formation was observed in neuron E at 25 hpf, neuron C at 26 hpf, neuron B at 27 hpf, and neuron A at 28 hpf. Scale bars: 100 µm. d TUNEL staining (panel a) and double immunostaining of zebrafish embryos expressing h4R-tau-GFP at different developmental stages was performed using polyclonal antibody against Caspase 9 and monoclonal antibody against GFP (panel b). Scale bar: 50 µm