[Cloning and expression of Vibrio cholerae zonula occludens toxin (zot) gene in Escherichia coli].

Two recombinant plasmids containing the cloned PCR-amplifled Vibrio cholerae zonula occludens toxin (zot) gene was constructed in orientation providing its transcription from lac-promoter. One of them contained also its own zot promoter. The third plasmid was obtained by subcloning a Vibrio cholerae DNA fragment including intact zot and ace (accessory cholera enterotoxin) genes. The expression levels of the cloned genes in Escherichia coli varied depending on a promoter type, host strain and culture conditions. The human intestinal cell line CaCo2 appeared to be a suitable model for assessing the biological activity of toxin preparations. The product of zot gene possessed a marked activity in respect to CaCo2 in spite of the lack of the molecule cleavage and transport of its toxic C-terminal part from alien host cells into the culture media. The constructed recombinant plasmids can be used as a source of molecular hybridization probes; and E.col transformants carrying those plasmids can serve in zot purification both for the scientific and practical purposes.