Shi M, Zhao S, Wang Z-H, Stanley D, Chen X-X
Ministry of Agriculture Key Lab of Agricultural Entomology, Institute of Insect Sciences, Zhejiang University, Hangzhou, China.
Biological Control of Insects Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Columbia, MO, USA.
Insect Mol Biol. 2016 Dec;25(6):679-688. doi: 10.1111/imb.12252. Epub 2016 Jul 4.
Thioredoxins (Trxs) are a family of small, highly conserved and ubiquitous proteins involved in protecting organisms against toxic reactive oxygen species. In this study, a typical thioredoxin gene, PxTrx, was isolated from Plutella xylostella. The full-length cDNA sequence is composed of 959 bp containing a 321 bp open reading frame that encodes a predicted protein of 106 amino acids, a predicted molecular weight of 11.7 kDa and an isoelectric point of 5.03. PxTrx was mainly expressed in larval Malpighian tubules and the fat body. An enriched recombinant PxTrx had insulin disulphide reductase activity and stimulated Human Embryonic Kidney 293 (HEK293) cell proliferation. It also protected supercoiled DNA and living HEK293 cells from H O -induced damage. Parasitization by Cotesia vestalis and injections of 0.05 and 0.01 equivalents of C. vestalis Bracovirus (CvBv), the symbiotic virus carried by the parasitoid, led to down-regulation of PxTrx expression in host fat body. Taken together, our results indicate that PxTrx contributes to the maintenance of P. xylostella cellular haemostasis. Host fat body expression of PxTrx is strongly attenuated by parasitization and by injections of CvBv.
硫氧还蛋白（Trxs）是一类小型、高度保守且普遍存在的蛋白质家族，参与保护生物体免受有毒活性氧的侵害。在本研究中，从小菜蛾中分离出一个典型的硫氧还蛋白基因PxTrx。其全长cDNA序列由959个碱基对组成，包含一个321个碱基对的开放阅读框，该开放阅读框编码一个预测的由106个氨基酸组成的蛋白质，预测分子量为11.7 kDa，等电点为5.03。PxTrx主要在幼虫的马氏管和脂肪体中表达。富集的重组PxTrx具有胰岛素二硫键还原酶活性，并刺激人胚肾293（HEK293）细胞增殖。它还能保护超螺旋DNA和活的HEK293细胞免受H₂O₂诱导的损伤。菜蛾盘绒茧蜂寄生以及注射该寄生蜂携带的共生病毒菜蛾盘绒茧蜂杆状病毒（CvBv）的0.05和0.01当量，会导致宿主脂肪体中PxTrx表达下调。综上所述，我们的结果表明PxTrx有助于维持小菜蛾细胞的内环境稳定。寄生以及注射CvBv会强烈减弱宿主脂肪体中PxTrx的表达。
