Fig. 3. Arrow provides a degradation signal. In all experiments described here, dpp-Gal4 was used as a driver and staining was with anti-Wingless. (A) Wingless stabilization by Frizzled2 as shown in Fig. 2A (in an imaginal disc of the genotype dpp-Gal4 UAS-Frizzled2-FLAG). (B) Wingless is reduced to a range shorter than in wild-type tissue by co-expression of Arrow with Frizzled2. The range is shorter in the dpp-Gal4 domain (marked with a double-headed arrow) than in neighbouring tissue. (C) Wingless accumulates if endocytosis is blocked in the otherwise same genotype as in B. Here, endocytosis was blocked by culturing the larvae at 32°C for 3 hours in a shi[ts] hemizygous background. No accumulation was seen in the identical genotype cultured at 25°C throughout (not shown). (D) Activated Armadillo (Arm^*) does not affect the distribution of Frizzled2-stabilized Wingless.