MAPT and supranuclear palsy, progressive, 1: Notably, while no combination of tau isoform overexpression and Aβ is sufficient to recapitulate all dysregulated pathways seen in our analysis of RNA-seq data from AD and PSP patients, overexpression of either isoform is sufficient to cause dysregulation in TE expression, though this effect is more prominent with 4R tau overexpression.