Reduction in Cul1 function causes apoptosis. (A) Wild-type third instar wing discs stained with acridine orange show very little cell death. (B) Discs with reduced Cul1 function due to mCul1 overexpression have a high level of cell death. (C) Small wing phenotype due to mCul1 expression (MS1096/Y;UAS-mCul1/+). (D) Partial suppression when the anti-apoptotic protein p35 is co-expressed (MS1096/Y;UAS-mCul1/UAS-p35).