HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 291/3/R844    most recent 00739.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science 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 ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Janech, M. G. Articles by Ploth, D. W. Search for Related Content PubMed PubMed Citation Articles by Janech, M. G. Articles by Ploth, D. W.

WATER AND ELECTROLYTE HOMEOSTASIS

Cloning and functional characterization of a second urea transporter from the kidney of the Atlantic stingray, Dasyatis sabina

¹Marine Biomedicine and Environmental Sciences Center, Departments of ²Medicine and ³Pharmacology and Experimental Therapeutics, Medical University of South Carolina, and ⁴Ralph H. Johnson, Department of Veteran's Affairs Medical Center, Charleston, South Carolina

Submitted 19 October 2005 ; accepted in final form 10 April 2006

The cloning of cDNAs encoding facilitated urea transporters (UTs) from the kidneys of the elasmobranchs indicates that in these fish renal urea reabsorption occurs, at least in part, by passive processes. The previously described elasmobranch urea transporter clones from shark (shUT) and stingray (strUT-1) differ from each other primarily because of the COOH-terminus of the predicted strUT-1 translation product being extended by 51-amino acid residues compared with shUT. Previously, we noted multiple UT transcripts were present in stingray kidney. We hypothesized that a COOH terminally abbreviated UT isoform, homologous to shUT, would also be present in stingray kidney. Therefore, we used 5'/3' rapid amplification of cDNA ends to identify a 3'UTR-variant (strUT-1a) of the cDNA that encodes (strUT-1), as well as three, 3'UTR-variant cDNAs (strUT-2a,b,c) that encode a second phloretin-sensitive, urea transporter (strUT-2). The 5'UTR and the first 1,132 nucleotides of the predicted coding region of the strUT-2 cDNAs are identical to the strUT-1 cDNAs. The remainder of the coding region contains only five novel nucleotides. The strUT-2 cDNAs putatively encode a 379-amino acid protein, the first 377 amino acids identical to strUT-1 plus 2 additional amino acids. We conclude that 1) a second UT isoform is expressed in the Atlantic stingray and that this isoform is similar in size to the UT previously cloned from the kidney of the dogfish shark, and 2) at least five transcripts encoding the 2 stingray UTs are derived from a single gene product through alternative splicing and polyadenylation.

elasmobranch; euryhaline; alternative splicing; osmoregulation

This article has been cited by other articles:

				T. M. Rodela, J. S. Ballantyne, and P. A. Wright Carrier-mediated urea transport across the mitochondrial membrane of an elasmobranch (Raja erinacea) and a teleost (Oncorhynchus mykiss) fish Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2008; 294(6): R1947 - R1957. [Abstract] [Full Text] [PDF]