Generation of transgenic medaka expressing claudin7-EGFP for imaging of tight junctions in living medaka embryos

Abstract

The tight junction (TJ) is a specialized cell-cell adhesion structure in epithelial and endothelial sheets unique to the chordates and functions as a barrier of fluidal diffusion across the cell sheets. In order to study the dynamics of TJ formation in vivo during embryogenesis, we have generated a transgenic medaka line that expresses claudin-7 protein fused to enhanced green fluorescent protein under the regulation of the red seabream beta-actin promoter in transparent medaka embryos. Claudins contain four transmembrane domains and have been identified as the key molecules that dictate the function of TJs. This transgenic medaka line will thus be useful for imaging of TJs in living embryos and hence in screening for mutations affecting cell-cell adhesion.

Claudin-6, -10d, and -10e contribute to seawater acclimation in the euryhaline puffer fishTetraodon nigroviridis

“…However, in fishes, the nature of TJ proteins in the skin and the contribution that they make to its physiological function is poorly understood. Nevertheless, to date, approximately 36 genes encoding TJ proteins (including Cldns, occludin and ZO-1), have been reported in the skin of at least six different teleost species (Bagherie-Lachidan et al, 2008;Bagherie-Lachidan et al, 2009;Chasiotis et al, 2010;Chasiotis and Kelly, 2012;Clelland and Kelly, 2010;Loh et al, 2004;Miyamoto et al, 2009;Syakuri et al, 2013). Furthermore, transcript abundance of several putative 'tightening has been reported to increase in the skin of T. nigroviridis acclimated to a hyperosmotic environment versus those held in FW (Bagherie-Lachidan et al, 2008;BagherieLachidan et al, 2009).…”

Claudins in teleost fishes

“…However, early studies using transgenic medaka ( Oryzias latipes ) possessing cldn-7 fused to enhanced green fluorescent protein (GFP) allowed the first in vivo observations of TJ dynamics during the course of embryogenesis in a living animal 32 . In medaka embryos, cldn-7 was found to be expressed in the pronephric duct, otic vesicle, olfactory primordium and skin at stage 23 (~1 d and 17 h post fertilization) and at 2 dpf, cldn-7 was found localized to cell-cell junctions in the retina, neural tube and the skin 32 . More recently, a cldn-k fused GFP zebrafish model has been used to study myelination during development 33 .…”