The calanoid copepod, Acartia tonsa, is relatively sensitive to marine pollution. Glutathione S-transferase (GST) multifunctional enzyme, as a biomarker, play an important role in detoxification metabolism of exogenous substances. In the present study, GST-theta and GST-mu class homology genes (designated as AtGSTT1 and AtGSTM2) were identified and characterized from A. tonsa. The coding sequence of AtGSTT1 comprised 726 bp and encoded a putative protein of 241 amino acid residues. AtGSTM2 contained an open reading frame of 678 bp that encoded a putative 227 amino acid polypeptide. Both proteins contained a conserved GST-N domain and a GST-C domain. Structural analysis revealed the characteristic N-terminal G-site. Three-dimensional structure analysis showed that AtGSTT1 and AtGSTM2 have two typical domains of GST family: The βαβαββα topology structure at the N- terminus and the superhelical structure at the C- terminus. Subsequently, the expression levels of the two GST genes were detected in A. tonsa using real-time quantitative PCR after exposure to 1,2-dimethylnaphthalene (C2-NAPH) at different concentrations (0.574, 5.736 and 57.358 μg/L) for 24, 48, 72, and 96 h. AtGSTT1 mRNA expression was significantly up-regulated in a time-dependent manner and the highest mRNA expression occurred at 5.736 μg/L C2-NAPH exposure for 96 h. AtGSTM2 mRNA expression peaked at 72 h in 0.574 μg/L and 5.736 μg/L dose groups. The expression level of AtGSTM2 showed an increasing trend in a time-dependent manner at 57.358 μg/L of C2-NAPH. These results suggested that GST genes may play an important role in protecting A. tonsa from C2-NAPH pollution, and provide a theoretical basis for further study on the molecular mechanism of polycyclic aromatic hydrocarbon (PAHs) pollution on zooplankton.

中文翻译：

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海洋co足纲A虫的谷胱甘肽S-转移酶（GST）基因：响应1，2-二甲基萘的cDNA克隆和mRNA表达。

cal足类pe足动物A螨对海洋污染相对敏感。谷胱甘肽S-转移酶（GST）多功能酶作为生物标志物，在外源物质的排毒代谢中起着重要作用。在本研究中，从A.tonsa鉴定并鉴定了GST-theta和GST-mu类同源基因（分别命名为AtGSTT1和AtGSTM2）。AtGSTT1的编码序列包含726 bp，编码一个推测的241个氨基酸残基的蛋白。AtGSTM2包含一个678 bp的开放阅读框，编码一个假定的227个氨基酸的多肽。两种蛋白质均包含保守的GST-N结构域和GST-C结构域。结构分析揭示了特征性的N末端G位点。三维结构分析表明AtGSTT1和AtGSTM2具有GST家族的两个典型域：N端的βαβαββα拓扑结构和C端的超螺旋结构。随后，在不同浓度（0.574、5.736和57.358μg/ L）的1,2-二甲基萘（C2-NAPH）中暴露24小时后，使用实时定量PCR检测了A.tonsa中两个GST基因的表达水平。 ，48、72和96小时。AtGSTT1 mRNA的表达以时间依赖的方式显着上调，最高的mRNA表达发生在5.736μg/ L C2-NAPH暴露96 h时。在0.574μg/ L和5.736μg/ L剂量组中，AtGSTM2 mRNA表达在72 h达到峰值。AtGSTM2的表达水平以57.358μg/ L的C2-NAPH呈时间依赖性增加。这些结果表明，GST基因可能在保护扁桃体免受C2-NAPH污染方面起着重要作用，