Date of Graduation
Master of Science in Biology (MS)
Second Committee Member
Claudin proteins, a key element of tight junction complexes, are known to control paracellular permeability. In euryhaline fish, changes in claudin abundance and localization are critical during salinity acclimation. In seawater, a leaky paracellular pathway that facilitates sodium extrusion is hypothesized to be controlled by claudin proteins. The aim of this study was to evaluate the role of Claudin-10c, -10d -10e and Claudin-30 in gill function in freshwater (FW) and seawater (SW) rainbow trout (Oncorhynchus mykiss). I examined mRNA and protein abundance along with cellular localization. A tissue distribution survey showed that all of the claudins studied were predominantly expressed in gill tissue. Transcript and protein expression of Claudin-10s was significantly up-regulated after SW transfer, while no difference in Claudin-30 expressions was observed. In accordance with these expression patterns, in silico prediction showed that Claudin-10s could form cation-selective pores and thus be critical to sodium secretion in SW. Claudin-30 is known as a resistance forming claudin and its insensitivity to salinity suggests an epithelial barrier function in both FW and SW gills. In addition, immunofluorescence microscopy revealed that Claudin-10s are localized in association with the ionocytes in SW. Expression of Claudin-30 was restricted to intermediate cells on the gill filament. This study also suggest that claudins expression may be influenced by combination of both genetic and environmental factors.
Bujak, Joanna Katarzyna, "Functional Significance of Gill Claudin Proteins in Rainbow Trout (Oncorhynchus mykiss) Osmoregulation" (2015). Theses and Dissertations. 1135.