Effects of the forced expression of claudins 1 and 3 on their subcellular distribution, TER and macromolecular permeability. HT-29 cells were transduced with retroviral vectors that contained claudin-1, claudin-3, or empty vector (pBABE).

<p>(<b>A</b>) The cells were grown and total cell lysates were harvested and analyzed by immunoblotting for the expression of claudin-1 and claudin-3. The numbers represent the ratio of the optical density of claudin-transduced to empty vector-transduced cells normalized by α-tubulin. (<b>B</b>) Cells were grown on glass coverslips and processed under permeabilizing conditions for the immunofluorescence analysis of claudin-1 and claudin-3 distribution; bar: 5 µm. (<b>C</b>) Cells were grown on Transwell inserts and the TER was measured using the Millicel-ERS system. The bar graphs show the TER values normalized for the area of the insert with the blank value subtracted. (<b>D</b>) The cells were grown on glass coverslips and processed for immunofluorescence under non-permeabilizing conditions to evaluate macromolecular permeability using the anti-uvomorulin/E-cadherin antibody; bar: 10 µm. (<b>E</b>) Cells were grown on glass coverslips and processed under permeabilizing conditions for immunofluorescence analysis of E-cadherin distribution. The stained cells were viewed with <b><i>FV10i-O</i></b> confocal microscope. Error bars indicate the means ± SEM (n = 3); **p<0.01 as determined by an ANOVA.