Submitted on May 1, 2008
Revised on May 29, 2008
Accepted on June 4, 2008
Functional and structural characterization of the zebrafish Na+-sulfate cotransporter 1 (NaS1) cDNA and gene (slc13a1)
Daniel Markovich1*, Alessandro Romano, Carlo Storelli, and Tiziano Verri
1 University of Queensland
* To whom correspondence should be addressed. E-mail: d.markovich{at}uq.edu.au.
Sulfate plays an essential role during growth, development and cellular metabolism. In this study, we characterized the function and structure of the zebrafish (Danio rerio) Na+-sulfate cotransporter 1 (NaS1) cDNA and gene (slc13a1). Zebrafish NaS1 encodes a protein of 583 amino acids with 13 putative transmembrane domains. Expression of zebrafish NaS1 protein in Xenopus oocytes led to Na+-sulfate cotransport which was significantly inhibited by thiosulfate, selenate, molybdate and tungstate. Zebrafish NaS1 transport kinetics were: Vmax = 1731.670 ± 92.853 pmol sulfate/oocyte • hour and Km = 1.414 ± 0.275 mM for sulfate and Vmax = 307.016 ± 32.992 pmol sulfate/oocyte • hour, Km = 24.582 ± 4.547 mM and n (Hill coefficient) = 1.624 ± 0.354 for sodium. Zebrafish NaS1 mRNA is developmentally expressed in embryos from day 1 post fertilization and in the intestine, kidney, brain and eye of adult zebrafish. The zebrafish NaS1 gene slc13a1 contains 15 exons spanning 8716 bp. Characterization of the zebrafish NaS1 contributes to a greater understanding of sulfate transporters in a well-defined genetic model and will allow the elucidation of evolutionary and functional relationships among vertebrate sulfate transporters.
