This is a challenging possibility, yet, as we determined by sagittal sections of the adult fish brain (Supplementary Figs 1 and 2), her4. 1 and nbt promoters can lead to TAU expression in the majority of the neurons in the adult fish brain, and it is very unlikely that such a widespread expression would not include the neurons of the forebrain that are susceptible to Tauopathies. This evidence concerns the gene ERBB4 and tauopathy.