Fig. 3.

Effect of occludin siRNA on various transmembrane tight junction (TJ) protein and mRNA expression. A: siRNA occludin caused an increase in claudin-2 protein expression but did not affect claudins-1, -3, -5, and -8 protein expression as assessed by Western blot analysis. B: occludin depletion by siRNA transfection in Caco-2 monolayers did not affect the mRNA levels of claudins-1, -3, -5, and -8 as assessed by real-time PCR (4 days posttransfection). C: claudin-2 mRNA levels were significantly increased in occludin siRNA-transfected Caco-2 monolayers (means ± SE, n = 4). *P < 0.001 vs. control.