Roles of Slc13a1 and Slc26a1 sulfate transporters of eel kidney in sulfate homeostasis and osmoregulation in freshwater
Roles of Slc13a1 and Slc26a1 sulfate transporters of eel kidney in sulfate homeostasis and osmoregulation in freshwater
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DOI：
10.1152/ajpregu.00725.2004
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发表时间：
2005-08-01
影响因子：
2.8
通讯作者：
Hirose, S
中科院分区：
文献类型：
--
作者：
Nakada, T;Zandi-Nejad, K;Hirose, S
硫酸盐是所有生物体正常细胞生长和发育所必需的。我们已经证明，肾脏硫酸盐转运系统在广盐性鳗鱼中具有双重作用，即维持硫酸盐稳态和调节体液。为了阐明硫酸盐转运蛋白在硬骨鱼中的生理作用，我们克隆了哺乳动物肾脏硫酸盐转运蛋白Slc 13 a1（NaSi-1）和Slc 26 a1（Sat-1）的同源基因，并评估了它们的功能特征、组织定位和表达调控。从淡水鳗鱼肾cDNA文库中克隆了编码ajSlc 13 a1和ajSlc 26 a1的全长cDNA。非洲爪蟾卵母细胞中的功能表达揭示了预期的硫酸盐转运特征;此外，两种转运蛋白均被氯化汞抑制。北方印迹分析，原位杂交和免疫组织化学显示，强大的顶端和基底侧ajSlc 13 a1和ajSlc 26 a1，分别在近端小管内的淡水鳗鱼肾脏。表达显着减少后，从淡水到海水的鳗鱼转移;鳗鱼中的循环硫酸盐浓度又显着升高，在淡水与海水条件下相比（19毫米与1毫米）。因此，通过顶端ajSlc 13 a1和基底侧ajSlc 26 a1转运蛋白的硫酸盐重吸收可能有助于淡水调节广盐性鳗鱼，通过调节循环硫酸盐浓度。
Sulfate is required for proper cell growth and development of all organisms. We have shown that the renal sulfate transport system has dual roles in euryhaline eel, namely, maintenance of sulfate homeostasis and osmoregulation of body fluids. To clarify the physiological roles of sulfate transporters in teleost fish, we cloned orthologs of the mammalian renal sulfate transporters Slc13a1 (NaSi-1) and Slc26a1 (Sat-1) from eel ( Anguilla japonica) and assessed their functional characteristics, tissue localization, and regulated expression. Full-length cDNAs coding for ajSlc13a1 and ajSlc26a1 were isolated from a freshwater eel kidney cDNA library. Functional expression in Xenopus oocytes revealed the expected sulfate transport characteristics; furthermore, both transporters were inhibited by mercuric chloride. Northern blot analysis, in situ hybridization, and immunohistochemistry demonstrated robust apical and basolateral expression of ajSlc13a1 and ajSlc26a1, respectively, within the proximal tubule of freshwater eel kidney. Expression was dramatically reduced after the transfer of eels from freshwater to seawater; the circulating sulfate concentration in eels was in turn markedly elevated in freshwater compared with seawater conditions ( 19 mM vs. 1 mM). The reabsorption of sulfate via the apical ajSlc13a1 and basolateral ajSlc26a1 transporters may thus contribute to freshwater osmoregulation in euryhaline eels, via the regulation of circulating sulfate concentration.