Zonula Occludens Toxin (ZOT) inhibits intracellular trafficking of luciferase DNA in susceptible cells

Zonula occludnes toxin (Zot) is a protein elaborated by Vibrio Cholerae that modulates the opening of intercellular tight jucntions (tj). The mechanism by which Zot modulates tj involves rearrangement of the cytoskeleton with resultant polymerization of actin fibers via a PKC dependent pathway. Thus, Zot promotes an increase in tissue permeability and a reduction in transepithelial resistance by opening tj. Preliminary data suggests that Zot is a microtubule binding protein capable of modulating normal intracellular trafficking patterns. Using a luciferase trasnfection assay, various cell lines were transfected with luciferase DNA in the presence or absence of Zot. In addition, cells were exposed to Zot either before or after luciferase transfection. Three general phenotypes were observed. 410.4 cells showed a reduction in DNA expression either after pre- or post-treatment with Zot. DU145, NIH 3T3, and Cos-7 cells lakced DNA expression only when Zot was adminsitered after DNA transfection. In cells known to be deficient for the Zot receptor (i.e. T84) there was no observable effect on luciferase expression in the presence of Zot. These observations have led to the conculsion that Zot may inhibit DNA experession due to its ability to modulate intracellular trafficking.