脊尾白虾(Exopalaemon carinicauda)FAMeT基因在卵巢发育周期中的表达分析

The Expression Analysis of Farnesoic Acid O-Methyl Transferase (FAMeT) Gene During the Ovarian Development Cycles of E Exopalaemon carinicauda

关键词:  脊尾白虾  法尼酸甲基转移酶  卵巢发育  基因表达

Key words:  Exopalaemon carinicauda  Farnesoic acid O-methyltransferase (FAMeT)  Ovary reproductive  Expression level

摘要:

为了研究法尼酸甲基转移酶(Farnesoic acid O-methyltransferase, FAMeT)在脊尾白虾卵巢发育中的作用，采用实时荧光定量PCR方法分析连续3次繁殖过程中卵巢不同发育时期(Ⅰ−Ⅴ期)大颚器、卵巢和肝胰腺中FAMeT基因的表达规律。结果显示，FAMeT基因在鳃、心脏、肌肉、肝胰腺、卵巢、大颚器等组织中均有稳定的表达，其中，在鳃和大颚器的表达量显著高于其他组织；在卵巢发育周期内，FAMeT基因在大颚器、卵巢、肝胰腺中的表达量变化趋势基本一致，从Ⅰ−Ⅳ期逐渐下降，到Ⅴ期时表达量上调；在每个卵巢发育时期，FAMeT基因在大颚器中表达量最高，约为卵巢中表达量的20–30倍。研究结果表明，大颚器是合成FAMeT的主要组织，脊尾白虾繁殖过程中FAMeT基因主要在卵巢发育前期表达，可以合成大量甲基法尼酯(Methylfarnesoate, MF)，促进卵巢发育。

Abstract:

Methylfarnesoate (MF) is an important multifunctional substance in crustacean animals that plays an important role in the processes of reproduction, molting, and osmotic adjustment, etc. Farnesoic acid O-methyl transferase (FAMeT) is the key enzyme of MF synthesis which regulates the last step of the reaction, hence the expression level of the FAMeT is consistent with the amount of MF. To study the role of (FAMeT) in the ovarian development, we designed specific primers and employed quantitative real-time PCR to quantify the relative expression level of FAMeT in tissues of mandibular organ, ovary and hepatopancreas during different ovarian developmental phases in three consecutive reproductive process of Exopalaemon carinicauda. We found that FAMeT was expressed in all tested tissues, and that the mRNA level of FAMeT was the highest in gill followed by mandibular organ (MO). During an ovarian development cycle, the expression of FAMeT in mandibular organ, ovary and hepatopancreas decreased from phase I to IV and reached the lowest in phase IV before returning to a higher level in phase V. These results suggested that the expression of FAMeT mainly occurred in the early stage of the ovarian development cycle, and a large amount of FAMeT accelerated the production of MF. The accumulated MF then facilitated the ovarian development by promoting the expression of vitellogenin. Therefore FAMeT may play an important role in the ovarian development of E. carinicauda. Given that the expression of FAMeT mRNA was the highest at Stage I and V, and that Stage V was the Stage I of the next ovarian development cycle, we deduced that the expression of FAMeT could promote the synthesis of MF and boost the development of the ovary