Fig. 1. Expression of C-cadherin and its colocalization with cortical actin skeleton at the late blastula stage in Xenopus. (A) The assay system used in these experiments. (B) TCA-fixed animal caps were stained with an anti-C-cadherin monoclonal antibody (6B6) and visualized by Cy5-conjugated goat anti-mouse IgG. Shown here is an optical slice of a cleared animal cap imaged by LSM confocal microscope. Positive staining appears along cell-cell contacts as discrete punctae. (C) A grazing optical section in the plane of a cell membrane shows punctae en face (arrows). (D) Cells disaggregated in calcium- and magnesium-free saline lose surface cadherin. (E) Upon addition of calcium and magnesium, cells start to reaggregate. Two aggregating cells are shown at different angles. The membranes lining the site of initial adhesion between the cells produce punctae containing C-cadherin. (F) Cells on the blastocoelic surface of the animal cap stained with monoclonal antibody 6B6 against C-cadherin (red) and phalloidin. The two images are merged in the lower-left panel. Yellow areas indicate colocalization of F-actin and C-cadherin. (G) The areas outlined in the merged image shown at high magnification. Arrows highlight colocalization of F-actin and C-cadherin. Scale bars: 20 µm in A-E; 10 µm in F,G.