Fig. 8.

E-cadherin junctions are required for branching morphogenesis. A: Schematic representation of E-cadherin with five extracellular domains (EC1-EC5), a transmembrane region (T), and an intracellular cytoplasmic domain (Cyto). B: Representative phase microscopy of control (a,b) and EC5 function blocking antibody-treated (c) SMG organ cultures. Buds were counted after treatment with the function blocking antibody or Rat IgG and normalized to time zero. A significant decrease (65%) in the number of buds in SMGs treated with the EC5 function blocking antibody (c,d) compared to control rat IgG (a,d) was detected (ANOVA, **P < 0.05). Bar graphs represent one of three independent experiments, with an n = 36. C: Organ cultures were incubated with either rat IgG or the function blocking antibody to EC5, stained with FITC-derivatized secondary rat antibodies and analyzed by confocal microscopy. Size bar = 10 μm. D: EC5 and rat IgG-treated glands were extracted with Triton buffer and Triton-soluble (S) and -insoluble (I) fractions were analyzed for E-cadherin by Western blot. The bar graph depicts four independent experiments (filled bars, Rat IgG treated; unfilled bars, EC5 treated) with values plotted ± SEM. E: SMGs were extracted in Triton extraction buffer and immunoblotted for E-cadherin and β-actin expression. The bar graph depicts the ratio of E-cadherin to β-actin expression with the data normalized to rat IgG and plotted ± SEM.