Authors: Joshua Hutchins, Kevin Wong
Mentors: Dario Mizrachi
Insitution: Brigham Young University
Tight junctions (TJ’s) are composed of mainly three types of cell-adhesion molecules (CAMs) that regulate paracellular permeability in epithelial and endothelial cells. These are claudins (CLDNs), occludin (OCLN), and junctional adhesion molecules (JAMs).There are, however, several (27) isoforms of the claudin molecule, all of which are suspected to have different strengths and other properties in cell adhesion. Currently, the comparative strength of the interactions between different CAMs are unknown and no easily replicable model of a TJ has been created. To address this question we resourced to bacterial expression of these mammalian proteins. MG1655 E. coli cells (with flagellum) were transformed to express claudins 1, 2, 3, 5, and 10 as well as occludin and plated on 0.2% agar plates, allowing them to swim overnight. This allowed for a qualitative spectrum of strengths of the CAMs based on how far the cells were able to spread throughout the plate. Cells that interacted strongly swam less. This technique was applied to the case of the Atlantic Salmon. It swims both in fresh and ocean water. As it transitions, the TJs in its skin changes its composition of claudins. We were able to determine that the set of claudins employed during ocean water swimming are capable of stronger strength. This is consistent with the changes in osmolarity dictated by the amount of solute in the ocean water.