Expression of biomineralization-related ion transport genes in Emiliania huxleyi
Expression of biomineralization-related ion transport genes in Emiliania huxleyi
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DOI：
10.1111/j.1462-2920.2011.02561.x
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发表时间：
2011-12-01
影响因子：
5.1
通讯作者：
Brownlee, Colin
中科院分区：
文献类型：
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作者：
Mackinder, Luke;Wheeler, Glen;Brownlee, Colin
海洋浮游植物虎纹草的生物矿化是一个严格控制的细胞内过程。球石产生的分子基础仍然相对未知，尽管它在全球生物地球化学循环中的重要性以及对PCO(2)水平增加的不同敏感性已经被很好地记录下来。本研究利用定量逆转录聚合酶链式反应技术，研究了几个候选钙、氢和无机碳转运基因在湖北龙须草中的作用。为了改变方解石的产量，对两对同源的钙化和非钙化E.huxleyi菌株以及在不同钙离子浓度下生长的菌株进行了差异基因表达分析。我们发现钙化与属于溶质载体4(SLC4)家族的HCO3-转运蛋白、属于CAX交换器家族的钙/H+交换器和空泡H+-ATPase的持续上调有关。我们还发现球虫相关蛋白GPA在钙化细胞中表达下调。这些数据提供了强有力的证据，表明这些基因在虎纹埃希菌的生物矿化过程中发挥了关键作用。基于基因表达数据和目前的文献，提出了一个与生物矿化相关的离子在球石中传输的工作模型。
Biomineralization in the marine phytoplankton Emiliania huxleyi is a stringently controlled intracellular process. The molecular basis of coccolith production is still relatively unknown although its importance in global biogeochemical cycles and varying sensitivity to increased pCO(2) levels has been well documented. This study looks into the role of several candidate Ca2+, H+ and inorganic carbon transport genes in E. huxleyi, using quantitative reverse transcriptase PCR. Differential gene expression analysis was investigated in two isogenic pairs of calcifying and non-calcifying strains of E. huxleyi and cultures grown at various Ca2+ concentrations to alter calcite production. We show that calcification correlated to the consistent upregulation of a putative HCO3- transporter belonging to the solute carrier 4 (SLC4) family, a Ca2+/H+ exchanger belonging to the CAX family of exchangers and a vacuolar H+-ATPase. We also show that the coccolith-associated protein, GPA is down-regulated in calcifying cells. The data provide strong evidence that these genes play key roles in E. huxleyi biomineralization. Based on the gene expression data and the current literature a working model for biomineralization-related ion transport in coccolithophores is presented.