title: Cloning of rainbow trout SLC26A1: involvement in renal sulfate secretion.
abstract: The kidney plays an important role in ion regulation in both freshwater and seawater fish. However, ion transport mechanisms in the teleost kidney are poorly understood, especially at the molecular level. We have cloned a kidney-specific SLC26 sulfate/anion exchanger from rainbow trout (Oncorhynchus mykiss) that is homologous to the mammalian SLC26A1 (Sat-1). Excretion of excess plasma sulfate concentration after Na2SO4 injection corresponded to significantly higher expression of the cloned SLC26A1 mRNA. Detailed morphological observation of rainbow trout renal tubules was also performed by light microscopy and transmission electron microscopy. According to the structure of brush border and tubular system in the cytoplasm, renal tubules of rainbow trout were classified into proximal tubule first and second (PI and PII) segments and distal tubules. In situ hybridization revealed that SLC26A1 anion exchanger mRNA is specifically localized in the PI segment of kidneys from both seawater- and freshwater-adapted rainbow trout. With immunocytochemistry, Na+-K+-ATPase and vacuolar-type H+-ATPase were colocalized to the same cells and distributed in the basolateral and the apical membranes, respectively, of the cells where the SLC26A1 mRNA expressed. These findings suggest that the cloned kidney-specific SLC26A1 is located in kidney proximal tubules and is involved in excretion of excess plasma sulfate in rainbow trout.
authors.affiliation: Dept. of Biological Sciences, Univ. of Alberta, Edmonton, Alberta, Canada T6G 2E9.
authors.forename: Fumi
authors.initials: F
authors.lastname: Katoh
authors.forename: Martin
authors.initials: M
authors.lastname: Tresguerres
authors.forename: Kyung Mi
authors.initials: KM
authors.lastname: Lee
authors.forename: Toyoji
authors.initials: T
authors.lastname: Kaneko
authors.forename: Katsumi
authors.initials: K
authors.lastname: Aida
authors.forename: Greg G
authors.initials: GG
authors.lastname: Goss
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D015152:Blotting, Northern; D015153:Blotting, Western; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007668:Kidney / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism*; D014018:Tissue Distribution; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D013431:Sulfates; D025262:Vacuolar Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase