Fig. 2. Mouse E-cadherin functions as a cell adhesion molecule in Drosophila. cl-8 cells and cl8mEcad cells induced to express high levels of E-cadherin by addition of Cu²⁺ to the medium, were stained for E-cadherin (A), Arm (B) and -catenin (C). In cl-8 cells, mouse E-cadherin was not expressed and Arm and -catenin were barely detectable by immunofluorescence. In cl8mEcad cells, all three proteins were highly concentrated at cell-cell contacts. Note that -catenin staining was strongly increased in cl8mEcad cells although the total amount of -catenin was increased only twofold. This finding can be explained by the diffuse, mostly cytosolic localization of -catenin in cl-8 cells (see Fig. 1C), which leads to a very weak immunofluorescence signal.