Na+/HCO3− cotransporter 1 (nbce1) isoform gene expression during smoltification and seawater acclimation of Atlantic salmon
Na+/HCO3− cotransporter 1 (nbce1) isoform gene expression during smoltification and seawater acclimation of Atlantic salmon
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DOI：
10.1007/s00360-022-01443-8
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发表时间：
2022-06
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影响因子：
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通讯作者：
J. Breves;Ian S. H. McKay;Victor Koltenyuk;Nastasia N Nelson;S. Lema;S. McCormick
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文献类型：
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作者：
J. Breves;Ian S. H. McKay;Victor Koltenyuk;Nastasia N Nelson;S. Lema;S. McCormick
大西洋鲑鱼（Salmo salar）的生活史包括一个最初的淡水阶段（parr），在春季作为小鲑鱼迁移到海洋环境之前。渗透调节系统的发展将最终支持幼鱼进入海洋栖息地后的生存，这是熏蒸的一个关键方面。虽然所有广盐物种获得海水耐受性需要特定离子泵、转运体和通道的协同活动，但Na+/HCO3−共转运体1 （Nbce1）对盐度适应的贡献仍未得到解决。在这里，我们研究了三种ena +/HCO3−共转运蛋白1亚型的分支和肠道表达，分别为nbce1.1,-1.2a和1.2b。考虑到Nbce1在支持离子细胞吸收环境Na+中的作用，我们首先假设分支Nbce1转录物（nbce1.2a）的表达在鲑鱼经历熏蒸和海水暴露后会减弱。在不同的两年中，我们观察到鳃Na+/K+- atp酶活性、Na+/K+/2Cl -共转运蛋白1和囊性纤维化跨膜调节剂1在春季的表达增加，而nbce1.2a的表达没有随之变化。尽管如此，幼崽和幼崽在海水暴露后2天内，树枝上的nbce1.2水平有所下降。在肠道中，从春季到夏季，前肠中nbce1.1的基因转录丰度增加，而后肠和幽门盲肠中则没有，海水暴露对肠道中nbce1.1和1.2的表达表现出季节依赖性的转录调节。总的来说，我们的数据表明，所有三种bce1亚型的组织特异性调节是对海水的适应性反应的基础。
The life history of Atlantic salmon (Salmo salar) includes an initial freshwater phase (parr) that precedes a springtime migration to marine environments as smolts. The development of osmoregulatory systems that will ultimately support the survival of juveniles upon entry into marine habitats is a key aspect of smoltification. While the acquisition of seawater tolerance in all euryhaline species demands the concerted activity of specific ion pumps, transporters, and channels, the contributions of Na+/HCO3−cotransporter 1 (Nbce1) to salinity acclimation remain unresolved. Here, we investigated the branchial and intestinal expression of threeNa+/HCO3−cotransporter 1isoforms, denotednbce1.1,-1.2a, and-1.2b. Given the proposed role of Nbce1 in supporting the absorption of environmental Na+by ionocytes, we first hypothesized that expression of a branchialnbce1transcript (nbce1.2a) would be attenuated in salmon undergoing smoltification and following seawater exposure. In two separate years, we observed spring increases in branchial Na+/K+-ATPase activity,Na+/K+/2Cl−cotransporter 1, andcystic fibrosis transmembrane regulator 1expression characteristic of smoltification, whereas there were no attendant changes innbce1.2aexpression. Nonetheless, branchialnbce1.2alevels were reduced in parr and smolts within 2 days of seawater exposure. In the intestine, gene transcript abundance fornbce1.1increased from spring to summer in the anterior intestine, but not in the posterior intestine or pyloric caeca, andnbce1.1and-1.2bexpression in the intestine showed season-dependent transcriptional regulation by seawater exposure. Collectively, our data indicate that tissue-specific modulation of all threenbce1isoforms underlies adaptive responses to seawater.