Cloning of two carboxylesterase cDNAs from the swimming crab Portunus trituberculatus: Molecular evidences for their putative roles in methyl farnesotae degradation

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• 作者：Tian Tao ; Xi Xie ; Mingxin Liu ; Qinghua Jiang ; Dongfa Zhu ; ^{zhudongfa@nbu.edu.cn}
• 关键词：P. trituberculatus ; Carboxylesterase ; cDNA clone ; MF degradation ; Expression analysis
• 刊名：Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：203
• 期：Complete
• 页码：100-107
• 全文大小：1656 K
• 卷排序：203

文摘

The sesquiterpenoid methyl farnesoate (MF) is the unepoxidized form of insect juvenile hormone (JH) III, and is considered an equivalent of JH in crustaceans. Degradation of MF is similar to that of JH which occurs through ester hydrolysis by specific carboxylesterases (CXEs). In this study, the full-length cDNAs of two JH esterase-like CXEs were cloned from the swimming crab, Portunus trituberculatus. The predicted amino acid sequences of the two PtCXEs contain the conserved motifs including catalytic triad and oxyanion hole, which are the hallmark of the CXE family proteins. The phylogenetic analysis showed that the two PtCXEs may belong to the hormone/semiochemical processing group of CXE family, indicating their possible roles on metabolism of hormones. Transcripts of both PtCXEs were most abundant in hepatopancreas and the PtCXE2 was also highly expressed in ovary. The mRNA levels of two PtCXEs in hepatopancreas were induced by in vivo MF treatment and eyestalk ablation, further indicating their potential in degrading MF. However, during the ovarian maturation, expression of the two PtCXEs increased significantly in the early-vitellogenic stage, prior to the remarkable rise in hemolymph MF titer reported by our previous studies. Taken together, our results suggest that the two PtCXEs can potentially serve as the MF esterases, but their catalytic activity may not be restricted to MF.