Aquaporin-3 expressed in the basolateral membrane of gill chloride cells in Mozambique tilapia Oreochromis mossambicus adapted to freshwater and seawater
Aquaporin-3 expressed in the basolateral membrane of gill chloride cells in Mozambique tilapia Oreochromis mossambicus adapted to freshwater and seawater
复制标题
DOI：
10.1242/jeb.01684
复制
发表时间：
2005-07
影响因子：
2.8
通讯作者：
S. Watanabe;T. Kaneko;K. Aida
中科院分区：
文献类型：
--
作者：
S. Watanabe;T. Kaneko;K. Aida
摘要我们利用逆转录-聚合酶链式反应(RT-PCR)从莫桑比克罗非鱼的鳃中克隆了哺乳动物水通道蛋白-3(AQP3)的同源物。推导的氨基酸序列与其他脊椎动物AQP3同源物的同源性在-75%之间。RT-PCR结果表明，适应淡水和海水的罗非鱼AQP3基因在脑、垂体、肾、脾、肠、皮肤、眼和鳃等组织中均有表达。我们还利用非洲爪哇卵母细胞作为体外转录的cRNA表达系统，研究了罗非鱼AQP3的功能特性。表达AQP3基因的非洲爪哇卵母细胞的渗透透性(PF)约为对照卵母细胞的30倍，经0.3 mmol L-1 HgCl2处理后，渗透率可被抑制80%。鳃上皮细胞的光镜免疫细胞化学显示，罗非鱼AQP3在FW和SW适应的罗非鱼的鳃氯细胞中表达。电子显微镜免疫细胞化学进一步证明罗非鱼AQP3定位于鳃氯细胞的基侧膜上。AQP3在鳃氯细胞中的基侧定位表明，AQP3参与了调节体积变化和渗透接受，从而可能触发氯细胞的功能分化。
SUMMARY We have cloned a homologue of mammalian aquaporin-3 (AQP3) from gills of Mozambique tilapia using a reverse transcription-polymerase chain reaction (RT-PCR). The deduced amino acid sequence shared 64–75% homology with other vertebrate AQP3 homologues. RT-PCR revealed that tilapia AQP3 was expressed in the brain, pituitary, kidney, spleen, intestine, skin, eye and gill in tilapia adapted to freshwater (FW) and seawater (SW). We also examined functional characteristics of tilapia AQP3 using Xenopus oocytes as an in vitro transcribed cRNA expression system. Osmotic water permeability (Pf) of Xenopus oocytes expressing tilapia AQP3 was about 30-fold higher than that of control oocytes, and was 80% inhibited by treatment with 0.3 mmol l–1 HgCl2. Light-microscopic immunocytochemistry of branchial epithelia revealed that tilapia AQP3 was expressed in gill chloride cells of FW- and SW-adapted tilapia. Electron-microscopic immunocytochemistry further demonstrated that tilapia AQP3 was localized in the basolateral membrane of gill chloride cells. Basolateral localization of AQP3 in gill chloride cells suggests that AQP3 is involved in regulatory volume changes and osmoreception, which could trigger functional differentiation of chloride cells.