QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online May 30, 2008
Journal of Experimental Biology 211, 1964-1968 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.017368

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tse, W. K. F. Articles by Wong, C. K. C. Search for Related Content PubMed PubMed Citation Articles by Tse, W. K. F. Articles by Wong, C. K. C. Social Bookmarking                         What's this?

The cloning of eel osmotic stress transcription factor and the regulation of its expression in primary gill cell culture

W. K. F. Tse, S. C. Chow and C. K. C. Wong^*

Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong

^* Author for correspondence (e-mail: ckcwong{at}hkbu.edu.hk)

Accepted 31 March 2008

In the present study, we aimed to clone an osmotic stress transcriptional factor (Ostf) from gill cells of Japanese eels. In addition, we measured its expression in Percoll^TM-gradient-isolated gill chloride (CC) and pavement (PVC) cells and determined the regulation of its expression in primary gill cell culture. Using degenerative primers and RACE techniques, we cloned a cDNA of 615bp, encompassing the coding sequence of Ostf (204 amino acids). The cloned Ostf1 DNA sequence shared 84% DNA homology with the Ostf1 of tilapia. In general, the basal Ostf expression level was found to be significantly higher in CCs than in PVCs. In the direct transfer of fish from freshwater to seawater, a significant but transient induction of Ostf mRNA in CCs and PVCs was measured after 6h of acclimation. Compared with gill CCs, the level of induction measured at PVCs was lower. In the seawater-to-freshwater transfer, no significant change in Ostf transcript levels was detected in either CCs or PVCs. To decipher the regulatory mechanism of Ostf expression, we conducted experiments using primary gill cell culture to specifically address the involvement of two putative osmosensors (i.e. intracellular ion strength/macromolecular crowding and cytoskeleton) in the regulation of Ostf expression. Hypertonic treatment using impermeable solutes (i.e. NaCl, 500mOsmoll^–1) induced Ostf mRNA expression in 6h, but no noticeable effect was measured using permeable solute (i.e. urea, 500mOsmoll^–1). The induction was transcriptionally regulated and was abolished by the addition of organic osmolytes (i.e. betaine, inositol or taurine) into the culture media. Addition of colchicine (an inhibitor of microtubule polymerization) to hypertonic (with added NaCl, 500mOsmoll^–1) cells reduced Ostf mRNA expression, suggesting that an increase in intracellular ionic strength and the integrity of the cytoskeleton are involved in the activation of Ostf mRNA expression in the cells. Collectively, the results of this study reveal, for the first time, the differential expression of Ostf in isolated CCs and PVCs. The resulting knowledge can shed light on how Ostf participates in hyperosmotic adaptation in fish gills.

Key words: chloride cell, organic osmolyte, osmosensor, pavement cell, Ostf, transcription factor

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				S. C. Chow, L. Y. Ching, A. M. F. Wong, and C. K. C. Wong Cloning and regulation of expression of the Na+-Cl--taurine transporter in gill cells of freshwater Japanese eels J. Exp. Biol., October 15, 2009; 212(20): 3205 - 3210. [Abstract] [Full Text] [PDF]