Fig. 4. Exogenous expression of CRB3 induces the recruitment of multiple known tight junction proteins to tight junction structures containing ZO-1. (A) Cells were grown for 4 days post confluence on Transwell filters, fixed and stained with the indicated antibodies. Samples were analyzed by confocal microscopy, and apical confocal sections are shown. (B) Western blotting of tight junction proteins in png control vector and mycCRB3-expressing cells. 30 µg whole cell lysates were resolved by Nu-PAGE gel electrophoresis and immunoblotted for the indicated proteins as described in Material and Methods. Positions of molecular weight markers (in kDa) are shown on the left. Note that PALS1 runs as a characteristic doublet.