Functional characterization of a Niemann-Pick type C2 protein in the parasitoid wasp Micropfitis mediator  

作　　者：Yao Zheng Shan-Ning Wang Yong Peng Zi-Yun Lu Shuang Shan Ye-Qing Yang Rui-Jun Li Yong-Jun Zhang Yu-Yuan Guo 

机构地区：[1]State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China [2]College of Plant Protection, Agricultural University of Hebei, Baoding, Hebei Province, China [3]IPM Center of Hebei Province, Key Laboratory of Integrated Pest Management on Crops in Northern Region of North China, Ministry of Agriculture, Plant Protection Institute, Hebei Academy of Agricultural and Forestry Sciences, Baoding, Hebei Province, China [4]College of Plant Protection, China Agricultural University, Beijing, China

出　　处：《Insect Science》2018年第5期765-777,共13页昆虫科学（英文版）

基　　金：This work was supported by the China National ‘973＇ Basic Research Program （2012CBl14104） and the Na- tional Natural Science Foundation of China （31272048, 31471778, and 31672038）.

摘　　要：Niemann-Pick type C2 （NPC2） is a type of small soluble protein involved in lipid metabolism and triglyceride accumulation in vertebrates and arthropods. Recent stud- ies have determined that NPC2 also participates in chemical communication of arthropods. In this work, two novel NPC2 proteins （MmedNPC2a and MmedNPC2b） in Microplitis mediator were identified. Real-time quantitative PCR （qPCR） analysis revealed that Mmed- NPC2a was expressed higher in the antennae than in other tissues of adult wasps compared with MmedNPC2b. Subsequent immunolocalization results demonstrated that NPC2a was located in the lymph cavities of sensilla placodea. To further explore the binding charac- terization of recombinant MmedNPC2a to 54 candidate odor molecules, a fluorescence binding assay was performed. It was found MmedNPC2a could not bind with selected fatty acids, such as linoleic acid, palmitic acid, stearic acid and octadecenoic acid. How- ever, seven cotton volatiles, 4-ethylbenzaldehyde, 3,4-dimethylbenzaldehyde, fl-ionone, linalool, m-xylene, benzaldehyde and trans-2-hexen-l-al showed certain binding abilities with MmedNPC2a. Moreover, the predicted 3D model of MmedNPC2a was composed of seven r-sheets and three pairs of disulfide bridges. In this model, the key binding residues for oleic acid in CjapNPC2 of Camponotus japonicus, Lue68, Lys69, Lys70, Phe97, Thr103 and Phe127, are replaced with Phe85, Ser86, His87, Leu113, Tyr119 and Ile143 in MmedNPC2a, respectively. We proposed that MmedNPC2a in M. mediator may play roles in perception of plant volatiles.Niemann-Pick type C2 （NPC2） is a type of small soluble protein involved in lipid metabolism and triglyceride accumulation in vertebrates and arthropods. Recent stud- ies have determined that NPC2 also participates in chemical communication of arthropods. In this work, two novel NPC2 proteins （MmedNPC2a and MmedNPC2b） in Microplitis mediator were identified. Real-time quantitative PCR （qPCR） analysis revealed that Mmed- NPC2a was expressed higher in the antennae than in other tissues of adult wasps compared with MmedNPC2b. Subsequent immunolocalization results demonstrated that NPC2a was located in the lymph cavities of sensilla placodea. To further explore the binding charac- terization of recombinant MmedNPC2a to 54 candidate odor molecules, a fluorescence binding assay was performed. It was found MmedNPC2a could not bind with selected fatty acids, such as linoleic acid, palmitic acid, stearic acid and octadecenoic acid. How- ever, seven cotton volatiles, 4-ethylbenzaldehyde, 3,4-dimethylbenzaldehyde, fl-ionone, linalool, m-xylene, benzaldehyde and trans-2-hexen-l-al showed certain binding abilities with MmedNPC2a. Moreover, the predicted 3D model of MmedNPC2a was composed of seven r-sheets and three pairs of disulfide bridges. In this model, the key binding residues for oleic acid in CjapNPC2 of Camponotus japonicus, Lue68, Lys69, Lys70, Phe97, Thr103 and Phe127, are replaced with Phe85, Ser86, His87, Leu113, Tyr119 and Ile143 in MmedNPC2a, respectively. We proposed that MmedNPC2a in M. mediator may play roles in perception of plant volatiles.

关 键 词：binding ability chemical communication IMMUNOLOCALIZATION Microplitismediator NPC2 protein 3D model 

分 类 号：Q51[生物学—生物化学] Q969.54