Fig. 4. AEF-1 silences the activation of the Fbp1 EcRU by GAL4. Late third instar larval tissues from transgenic lines with the indicated genotypes (left-hand side) were histochemically stained for ß-galactosidase activity. Structures of the constructs in transgenic lines (left-hand side) are depicted as in Fig. 2. Disruptions of the binding sites for EcR/USP and AEF-1 are indicated with black crosses.