Background

Selenium (Se) appears in the selenoproteins in the form of selenocysteine (Sec) and is important for the growth and development of vertebrates. The present study characterized seven selenoproteins, consisting of the GPX1, GPX3, GPX4, SELENOW, SELENOP, TXNRD2 and TXNRD3 cDNAs in various tissues of yellow catfish, explored their regulation to dietary Se addition.

Methods

3′ and 5′ RACE PCR were used to clone full-length cDNA sequences of seven selenoprotein genes (GPX1, GPX3, GPX4, SELENOW, SELENOP, TXNRD2 and TXNRD3). Their molecular characterizations were analyzed, including conservative motifs and the SECIS elements. The phylogenetic trees were generated through neighbor-joining (NJ) method with MEGA 6.0 with 1000 bootstrap replications. Quantitative real-time PCR was used to explore their mRNA tissue distribution in the heart, anterior intestine, dorsal muscle, head kidney, gill, liver, brain, spleen and mesenteric fat. Yellow catfish (mixed sex) were fed diets with dietary Se contents at 0.03 (low Se), 0.25 (adequate Se) and 6.39 (high Se) mg Se/kg, respectively, for 12 weeks, and their spleen, kidney, testis and brain were used for the determination of the mRNA levels of the seven selenoproteins.

Results

The seven selenoproteins had similar domains to their corresponding members of other vertebrates. They were widely expressed in nine tissues, including heart, liver, brain, spleen, head kidney, dorsal muscle, mesenteric fat, anterior intestine and gill, but showed tissue-dependent expression patterns. Dietary Se addition affected the expression of the seven genes in spleen, kidney, testis and brain tissues of yellow catfish.

Conclusion

Taken together, our study demonstrated the characterization, expression and regulation of seven selenoproteins, which increased our understanding of the biological functions of Se and selenoproteins in fish.

中文翻译：

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黄鲶鱼 Pelteobagrus fulvidraco 中七个硒蛋白基因的表征和表达分析与膳食硒水平。

背景

硒 (Se) 以硒代半胱氨酸 (Sec) 的形式出现在硒蛋白中，对脊椎动物的生长发育很重要。本研究表征了黄鲶各种组织中的七种硒蛋白，包括 GPX1、GPX3、GPX4、SELENOW、SELENOP、TXNRD2 和 TXNRD3 cDNA，探讨了它们对膳食硒添加的调节。

方法

3' 和 5' RACE PCR 用于克隆七个硒蛋白基因（GPX1、GPX3、GPX4、SELENOW、SELENOP、TXNRD2 和 TXNRD3）的全长 cDNA 序列。分析了它们的分子特征，包括保守基序和 SECIS 元素。系统发育树是通过具有 1000 次引导复制的 MEGA 6.0 的邻居连接 (NJ) 方法生成的。定量实时PCR用于探索它们在心脏、前肠、背肌、头肾、鳃、肝、脑、脾和肠系膜脂肪中的mRNA组织分布。黄鲶鱼（混合性别）的日粮硒含量分别为 0.03（低硒）、0.25（充足硒）和 6.39（高硒）mg Se/kg，持续 12 周，它们的脾、肾、睾丸和大脑用于测定七种硒蛋白的 mRNA 水平。

结果

这七种硒蛋白与其他脊椎动物的相应成员具有相似的结构域。它们在九种组织中广泛表达，包括心脏、肝脏、大脑、脾脏、头肾、背肌、肠系膜脂肪、前肠和鳃，但显示出组织依赖性表达模式。膳食硒的添加影响了黄鲇鱼脾、肾、睾丸和脑组织中7个基因的表达。

结论

总之，我们的研究证明了七种硒蛋白的表征、表达和调节，这增加了我们对鱼中硒和硒蛋白生物学功能的理解。