Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao 266071, PR China.
Fish Shellfish Immunol. 2013 Sep;35(3):661-70. doi: 10.1016/j.fsi.2013.05.016. Epub 2013 Jun 14.
A selenium-dependent glutathione peroxidase cDNA was obtained from the ridgetail white prawn Exopalaemon carinicauda (EcGPx) by rapid amplification of cDNA ends (RACE) methods. The full-length cDNA of EcGPx was 946 bp, which contains a 5'-untranslated region (UTR) of 105 bp, 3'-UTR of 280 bp with a poly (A) tail, an open reading frame (ORF) of 561 bp, encoding a 186 amino-acid polypeptide with the predicted molecular weight of 21.35 kDa and estimated isoelectric point of 7.65. It involves a putative selenocysteine (U39) residue which is encoded by an opal codon, (220)TGA(222), and forms an active site with residues Q73 and W141. Sequence analysis revealed that a GPx signature motif 2 ((63)LAFPCNQF(70)), an extra active site motif ((151)WNFEKF(156)), two putative N-glycosylation site ((75)NNT(77) and (107)NGS(109)), and two arginine residues (R89 and R167) were observed in the EcGPx sequence. Comparison of amino acid sequences showed that white shrimp GPx is more closely related to GPx1 and GPx2 subgroups. Quantitative real-time RT-PCR analysis indicated that two glutathione antioxidant enzymes of E. carinicauda, glutathione peroxidase (designated EcGPx) and glutathione S-transferase (designated EcGST) were widely expressed in all the tested tissues, but showed different expression patterns. After Vibrio anguillarum and WSSV challenge, EcGPx and EcGST transcripts both in hemocytes and hepatopancreas increased in the first 6 h and 3 h, respectively. The results suggested that EcGPx and EcGST might be associated with the immune defenses to V. anguillarum and WSSV in E. carinicauda.
通过快速扩增 cDNA 末端（RACE）方法，从脊尾白虾（Exopalaemon carinicauda）中获得了一个依赖硒的谷胱甘肽过氧化物酶 cDNA（EcGPx）。EcGPx 的全长 cDNA 为 946bp，包含 105bp 的 5'非翻译区（UTR）、280bp 的 3'UTR 带有 poly（A）尾、561bp 的开放阅读框（ORF），编码一个 186 个氨基酸的多肽，预测分子量为 21.35kDa，估计等电点为 7.65。它涉及一个假定的硒代半胱氨酸（U39）残基，由一个终止密码子（220）TGA（222）编码，并与残基 Q73 和 W141 形成一个活性位点。序列分析表明，GPx 特征基序 2（（63）LAFPCNQF（70））、一个额外的活性位点基序（（151）WNFEKF（156））、两个假定的 N-糖基化位点（（75）NNT（77）和（107）NGS（109））和两个精氨酸残基（R89 和 R167）在 EcGPx 序列中被观察到。氨基酸序列比较表明，白虾 GPx 与 GPx1 和 GPx2 亚组更为密切相关。定量实时 RT-PCR 分析表明，两种谷胱甘肽抗氧化酶，谷胱甘肽过氧化物酶（命名为 EcGPx）和谷胱甘肽 S-转移酶（命名为 EcGST）在所有测试的组织中广泛表达，但表现出不同的表达模式。在鳗弧菌和 WSSV 攻击后，血细胞和肝胰腺中的 EcGPx 和 EcGST 转录物在第 6h 和第 3h 分别增加。结果表明，EcGPx 和 EcGST 可能与脊尾白虾对鳗弧菌和 WSSV 的免疫防御有关。
