| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Zoology, University of Florida, Gainesville, FL, USA
2 Department of Biological Sciences, Tokyo Institute of Technology, Yokohama, Japan
3 Department of Physiology and Biophysics and Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
4 Department of Biology, Georgia Southern University, Statesboro, GA, USA
* To whom correspondence should be addressed. E-mail: kchoe{at}zoo.ufl.edu.
In mammals, the Na+/H+ exchanger 3 (NHE3) is expressed with Na+/K+-ATPase in renal proximal tubules where it secretes H+ and absorbs Na+ to maintain blood pH and volume. In elasmobranchs (sharks, skates, and stingrays), the gills are the dominant site of pH and osmoregulation. This study was conducted to determine if epithelial NHE homologues exist in elasmobranchs, and if so, to localize their expression in gills and determine if their expression is altered by environmental salinity or hypercapnia. Degenerate primers and RT-PCR were used to deduce partial sequences of mammalian NHE2 and NHE3 homologues from the gills of the euryhaline Atlantic stingray (Dasyatis sabina). Real-time PCR was then used to demonstrate that mRNA expression of the NHE3 homologue increased when stingrays were transferred to low salinities, but not during hypercapnia. Expression of the NHE2 homologue did not change with either treatment. Rapid amplification of cDNA was then used to deduce the complete sequence of a putative NHE3. The 2744 base pair cDNA includes a coding region for a 2511 amino acid protein that is 70% identical to human NHE3 (SLC9A3). Antisera generated against the carboxyl tail of the putative stingray NHE3 labeled the apical membranes of Na+/K+-ATPase-rich epithelial cells, and acclimation to fresh water caused a redistribution of labeling in the gills. This study provides the first NHE3 cloned from an elasmobranch and is the first to demonstrate an increase in gill NHE3 expression during acclimation to low salinities, suggesting that NHE3 can absorb Na+ from ion-poor environments.
This article has been cited by other articles:
|
|
 |
|
  D. W. Baker, V. Matey, K. T. Huynh, J. M. Wilson, J. D. Morgan, and C. J. Brauner Complete intracellular pH protection during extracellular pH depression is associated with hypercarbia tolerance in white sturgeon, Acipenser transmontanus Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2009; 296(6): R1868 - R1880. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Inokuchi, J. Hiroi, S. Watanabe, P.-P. Hwang, and T. Kaneko Morphological and functional classification of ion-absorbing mitochondria-rich cells in the gills of Mozambique tilapia J. Exp. Biol., April 1, 2009; 212(7): 1003 - 1010. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Hiroi, S. Yasumasu, S. D. McCormick, P.-P. Hwang, and T. Kaneko Evidence for an apical Na-Cl cotransporter involved in ion uptake in a teleost fish J. Exp. Biol., August 15, 2008; 211(16): 2584 - 2599. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. H. Evans Teleost fish osmoregulation: what have we learned since August Krogh, Homer Smith, and Ancel Keys Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2008; 295(2): R704 - R713. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. B. Claiborne, K. P. Choe, A. I. Morrison-Shetlar, J. C. Weakley, J. Havird, A. Freiji, D. H. Evans, and S. L. Edwards Molecular detection and immunological localization of gill Na+/H+ exchanger in the dogfish (Squalus acanthias) Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R1092 - R1102. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. P. Choe and K. Strange Evolutionarily conserved WNK and Ste20 kinases are essential for acute volume recovery and survival after hypertonic shrinkage in Caenorhabditis elegans Am J Physiol Cell Physiol, September 1, 2007; 293(3): C915 - C927. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Donowitz and X. Li Regulatory Binding Partners and Complexes of NHE3 Physiol Rev, July 1, 2007; 87(3): 825 - 872. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Esaki, K. Hoshijima, S. Kobayashi, H. Fukuda, K. Kawakami, and S. Hirose Visualization in zebrafish larvae of Na+ uptake in mitochondria-rich cells whose differentiation is dependent on foxi3a Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2007; 292(1): R470 - R480. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
