Fig. 4.

Pbl acts downstream of Arm stabilization. (A) pbl repressed induction of DROPflash by arm and arm^* to 53% of control GFP. By contrast, Axin repressed arm-induced DROPflash to 26% of GFP control but was unable to repress arm^*-induced DROPflash, consistent with its destruction complex role. pblΔBRCT1, pblΔBRCT1&2, pblΔNLS, pblΔN-term and pblDH-PH repressed arm and arm^* induction of DROPflash (^*P<0.001), whereas GEF-mutated pblΔN-term^V531D, pblDH-PH^V531D and pbl^V531D did not (P>0.05). (B) In fly embryos, arm-Gal4 driven expression of the stabilized UAS-arm^S10 resulted in excess naked cuticle and few denticle belts. Co-expressing UAS-GFP did not alter this cuticle phenotype. Arrowhead indicates position of the ventral midline in B-D. (C) Co-expressing UAS-pblDH-PH diminished excess naked cuticle specification and increased the proportion of embryos with partial denticle belts, where denticles were continuous across the ventral midline. (D) Co-expressing UAS-pblDH-PH^V531D did not alter excess naked cuticle specification. (E) Quantification of denticle belt status in larval cuticles (n>100 for each cross). Cuticles representing the median phenotype for each genotype are shown in B-D. Error bars represent s.e.m.