Fig. 3.

Functional and structural interactions between Axin and Notch. (A-A″) Confocal images of Drosophila third instar wing imaginal discs expressing CeN and containing clones of Axin mutant cells. CeN is a chimera in which the intracellular domain of Notch, tagged with eGFP, is tethered to the membrane with CD8 (see text and Materials and Methods for details). A′ and A″ are higher magnifications of the boxed region in A: A′ is an apical and A″ a basal image. There is a reduction in apically located CeN but not in the overall amount or appearance of the vesicles in the basal image. The clones are highlighted by the loss of cytoplasmic eGFP. The punctate eGFP pattern represents CeN and the discs are stained with an antibody against the intracellular domain of Notch (NIC; red); merge is yellow. (B,C) Confocal images of third instar wing imaginal discs containing Axin clones (B) or Axin clones expressing Notch^RNAi (C) labelled by the absence of GFP (black areas). Note the expansion in the size of the Axin mutant clones when the amount of Notch protein is reduced by expression of Notch^RNAi. Scale bars: 100 μm in A; 200 μm in C for B,C; 25 μm in A″ for A′,A″.