Doxycycline-inducible β cell-specific overexpression of dominant-negative Smad3 (Smad3DN) prevents HFD-induced diabetes by decreasing β cell apoptosis, while overexpression of constitutively active Smad3 (Smad3CA) exacerbates diabetes with an increase in β cell apoptosis [38]. The gene discussed is SMAD3; the disease is diabetes mellitus.