Fig. 3.

Accumulation of Notch in the biosynthetic and secretory compartments in Catsup mutant clones. (A-B′) Catsup mutant clones genetically marked by absence of lacZ expression were generated in wing imaginal discs and examined for Notch accumulation (red; A,B) together with either the ER chaperone marker PDI-GFP (green; A′) or the Golgi marker sqh-Golgi-YFP (green; Golgi-YFP; B′), with corresponding merged images of Notch and the relevant organelle marker (A′,B′). (C-D′) Functional rescue of Notch trafficking defects in Catsup mutant clones expressing transgenic wild-type Catsup-V5. Homozygous Catsup mutant clones were produced in wing discs using the MARCM system (Lee and Luo, 2001) to express wild-type Catsup-V5 in the mutant clone cells, then immunostained for endogenous Notch (red; C,D), the V5 epitope tag, which marks mutant cells only (green; C′,D′), and examined for apical (C,C′) and basal (D,D′) accumulation of Notch and Catsup-V5. C′ and D′ show the corresponding merged Notch and Catsup-V5 signals. For each sample in A-D′, the corresponding confocal z-series showing the apicobasal distribution of signal(s) is included beneath the gray bar.