Fig. 3. Expression of exogenous CRB3 induces tight junction formation in MCF10A cells. (A) Indicated cell lines were grown until 4 days post confluent on Transwell filters. Cells were fixed and stained for the tight junction marker ZO-1. (B) Cell lines were grown until 4 days post confluent on Transwell filters, then fixed and stained for ß-catenin (green), ZO-1 (red) and cell nuclei (with DAPI, shown in blue). Images were analyzed by confocal microscopy and X-Y views are shown of basal and apical confocal slices. Nuclear staining is out of plane in the apical view. Note that ß-catenin staining circumscribes individual cells at the basal level. (C) Representative Z-stack images of samples shown in B.