Duan Yafei, Liu Ping, Li Jitao, Wang Yun, Li Jian, Chen Ping
Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, People's Republic of China.
Cell Stress Chaperones. 2014 May;19(3):367-77. doi: 10.1007/s12192-013-0464-5. Epub 2013 Oct 19.
Methyl farnesoate (MF), an analogue of the insect juvenile hormone III, is believed to play important roles in the regulation of the growth and reproductive development in crustaceans. Farnesoic acid O-methyltransferase (FAMeT) is the key enzyme in the juvenile hormone biosynthetic pathway, involved in the conversion of farnesoic acid (FA) to MF in the final step of MF synthesis. In this study, a FAMeT cDNA (named EcFAMeT) was cloned from the hemocytes of ridgetail white prawn Exopalaemon carinicauda by rapid amplification of cDNA ends (RACE) methods. The full-length cDNA of EcFAMeT was 1,620 bp, including contains a 5'-untranslated region (UTR) of 75 bp, 3'-UTR of 714 bp with a poly (A) tail, an open reading frame (ORF) of 831 bp, encoding a 276-amino-acid polypeptide with the predicted molecular weight of 31.57 kDa and estimated isoelectric point of 4.67. BLAST analysis revealed that amino acids of EcFAMeT shared high identity (75-90 %) with that of other crustaceans. Two conserved signatures domains of Methyltransf-FA superfamily were also identified in EcFAMeT. Real time quantitative RT-PCR analysis indicated that EcFAMeT could be detected in all the tested tissues and strongly expressed in hepatopancreas and ovary of E. carinicauda. After Vibrio anguillarum and WSSV challenge, EcFAMeT transcripts both in hemocytes and hepatopancreas increased significantly in the first 3 h, respectively. The results indicated that EcFAMeT might be associated with the immune defenses to V. anguillarum and WSSV in E. carinicauda.
法尼酸甲酯（MF）是昆虫保幼激素III的类似物，被认为在甲壳类动物的生长和生殖发育调节中发挥重要作用。法尼酸O-甲基转移酶（FAMeT）是保幼激素生物合成途径中的关键酶，在MF合成的最后一步参与法尼酸（FA）向MF的转化。在本研究中，通过cDNA末端快速扩增（RACE）方法从脊尾白虾Exopalaemon carinicauda的血细胞中克隆了一个FAMeT cDNA（命名为EcFAMeT）。EcFAMeT的全长cDNA为1620 bp，包括一个75 bp的5'-非翻译区（UTR）、一个带有poly（A）尾的714 bp的3'-UTR和一个831 bp的开放阅读框（ORF），编码一个276个氨基酸的多肽，预测分子量为31.57 kDa，估计等电点为4.67。BLAST分析表明，EcFAMeT的氨基酸与其他甲壳类动物的氨基酸具有高度同一性（75-90%）。在EcFAMeT中还鉴定出了甲基转移酶-FA超家族的两个保守特征结构域。实时定量RT-PCR分析表明，EcFAMeT在所有测试组织中均可检测到，在脊尾白虾的肝胰腺和卵巢中强烈表达。在用鳗弧菌和WSSV攻击后，血细胞和肝胰腺中的EcFAMeT转录本在最初3小时内均显著增加。结果表明，EcFAMeT可能与脊尾白虾对鳗弧菌和WSSV的免疫防御有关。
