Densitometric analysis of PSP/reg protein levels confirmed that there was a significant threefold increase in PSP/reg levels following overexpression of DN-HNF1A (for 48 h), and a significant decrease in PSP/reg levels following overexpression of DN-HNF4A (Figures 3E and 3F). The gene discussed is REG1A; the disease is supranuclear palsy, progressive, 1.