Figure 7.

Lack of VhaPRR causes cell packing defects and increases junctional E-Cadherin. (A, A′) E-Cadherin (red) levels are elevated in VhaPRR mutant clones at 32 h APF. Lack of β-gal (blue in A′) marks the clone region. Hexagonal packing is strongly impaired, with less hexagons but more pentagons and heptagons compared with the hexagonal wild-type cells outside the clone. The cell size is also variable. Note that the clone lies above a vein that also shows increased E-Cadherin levels. (B) Extracellular E-Cadherin (green) staining (without detergent) demonstrates increased surface levels. Here (B′) and in the remaining panels, β-gal is shown in red. (C, C′) Armadillo (Arm; green) is also increased inside the clones. (D–F) Antibody uptake experiments in prepupal wings show that E-Cadherin is readily endocytosed upon antibody binding. (D, D′) Apical sections of a prepupal wing with a chase carried out at 29°C shows that junctional E-Cadherin is elevated inside the mutant clones. (E, E′, F, F′) In more basal sections, the same clone displays a strong accumulation of E-Cadherin in intracellular vesicles (inside white circle in (E)), compared with the neighbouring wild-type tissue. (F) A x–z projection shows the increase of E-Cadherin both at adherens junctions and in intracellular vesicles in mutant clones. E-Cadherin-positive basal vesicles are rarely seen in wild-type cells.