Gene expression of Na+/H+ exchanger in zebrafish H+ -ATPase-rich cells during acclimation to low-Na+ and acidic environments.
Gene expression of Na+/H+ exchanger in zebrafish H+ -ATPase-rich cells during acclimation to low-Na+ and acidic environments.
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DOI：
10.1152/ajpcell.00358.2007
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发表时间：
2007-10
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影响因子：
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通讯作者：
Jia-Jiun Yan;M. Chou;T. Kaneko;P. Hwang
中科院分区：
文献类型：
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作者：
Jia-Jiun Yan;M. Chou;T. Kaneko;P. Hwang
在哺乳动物肾单位中，大部分Na（+）和HCO（3）（-）被近端小管细胞重吸收，其中Na（+）/H（+）交换器3（NHE 3）是主要参与者。NHEs在淡水鱼鳃Na（+）吸收/酸碱调节中的作用仍有争议。本研究利用功能基因组学方法克隆了斑马鱼nhe家族的全长cDNA并进行了序列测定。系统进化树分析表明，zNHE 1 -8与哺乳动物同源。通过RT-PCR分析和原位杂交/免疫细胞化学双/三重分析，只有斑马鱼NHE 3b在斑马鱼鳃中表达，并且与V-H（+）-ATPase共定位，而与Na（+）-K（+）-ATPase不共定位，表明富含H（+）-ATPase（HR）的细胞特异性表达NHE 3b。随后的定量RT-PCR分析表明，低Na（+）FW驯化分别上调和下调了鳃HR细胞znhe 3b和zatp 6v 0 c（H（+）-ATPase C亚基）的表达，而酸性FW则相反。总之，NHE 3b和H（+）-ATP酶可能都参与了斑马鱼鳃的Na（+）吸收/酸碱调节，就像哺乳动物的肾脏一样，但这两种转运蛋白的分配可能取决于鱼类适应的环境条件。
In mammalian nephrons, most of the Na(+) and HCO(3)(-) is reabsorbed by proximal tubular cells in which the Na(+)/H(+) exchanger 3 (NHE3) is the major player. The roles of NHEs in Na(+) uptake/acid-base regulation in freshwater (FW) fish gills are still being debated. In the present study, functional genomic approaches were used to clone and sequence the full-length cDNAs of the nhe family from zebrafish (Danio rerio). A phylogenetic tree analysis of the deduced amino acid sequences showed that zNHE1-8 are homologous to their mammalian counterparts. By RT-PCR analysis and double/triple in situ hybridization/immunocytochemistry, only zebrafish NHE3b was expressed in zebrafish gills and was colocalized with V-H(+)-ATPase but not with Na(+)-K(+)-ATPase, indicating that H(+)-ATPase-rich (HR) cells specifically express NHE3b. A subsequent quantitative RT-PCR analysis demonstrated that acclimation to low-Na(+) FW caused upregulation and downregulation of the expressions of znhe3b and zatp6v0c (H(+)-ATPase C-subunit), respectively, in gill HR cells, whereas acclimation to acidic FW showed reversed effects on the expressions of these two genes. In conclusion, both NHE3b and H(+)-ATPase are probably involved in Na(+) uptake/acid-base regulation in zebrafish gills, like mammalian kidneys, but the partitioning of these two transporters may be differentially regulated depending on the environmental situation in which fish are acclimatized.