In combination with Tn10\tetR^{hs.T:Hsim\VP16}, 30 minute heat shock at 6.5 hours of embryogenesis causes failure of head involution in early embryos, defects on the dorsal surface of the head and disruptions of the prothoracic denticle belts. When expression is driven by Tn10\tetR^{ey.3.5.T:Hsim\VP16}, causes a dramatically reduced and irregular eye. This phenotype can be prevented by 0.1μg/ml tetracycline, but not 0.01μg/ml tetracycline. The addition of tetracycline leads to the recovery of viable adults in a concentration-dependent manner.