Identification and functional analysis of a Hemolin like protein from Litopenaeus vannamei
Identification and functional analysis of a Hemolin like protein from Litopenaeus vannamei
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DOI：
10.1016/j.fsi.2014.12.004
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发表时间：
2015-03-01
影响因子：
4.7
通讯作者：
Xu, Xiaopeng
中科院分区：
文献类型：
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作者：
Zuo, Hongliang;Li, Haoyang;Xu, Xiaopeng
血液蛋白是一种特异性免疫蛋白，属于免疫球蛋白超家族，首次在昆虫中发现。越来越多的证据表明，血液素可被细菌和病毒感染激活，并可能在抗菌免疫中发挥重要作用。本文首次从凡纳滨对虾（Litopenaeus vannamei, LvHemolin）中鉴定出一种类似hemolin的蛋白。序列分析表明，LvHemolin与昆虫Hemolins具有较高的相似性，主要由7个免疫球蛋白（Ig）结构域组成，形成“马蹄形”三级结构。组织分布分析表明，LvHemolin主要表达于vannamei的胃、鳃、上皮和幽门盲肠。在受到病原体或刺激物刺激后，LvHemolin在鳃和胃中的表达均显著上调。凝集分析表明，从大肠杆菌中纯化的重组LvHemolin蛋白在Ca2+存在下可以加速副溶血性弧菌、E. coil、金黄色葡萄球菌和枯草芽孢杆菌的凝集。为了验证LvHemolin在体内的免疫功能，我们给对虾注射了基因特异性的dsRNA，然后用白斑综合征病毒（WSSV）或副溶血性弧菌（V.副溶血性弧菌）攻毒。结果表明，LvHemolin的沉默可增加致病菌侵染对虾的累积死亡率，并增加WSSV在对虾组织中的拷贝数。这说明，在对虾对细菌和病毒感染的先天免疫防御中，血液素可能起着重要的作用。(C) 2014 Elsevier Ltd.版权所有。
Hemolin is a specific immune protein belonging to immunoglobulin superfamily and firstly identified in insects. Growing evidences suggest that Hemolin can be activated by bacterial and viral infections and may play an important role in antimicrobial immunity. In this paper, we firstly identified a Hemolin-like protein from Litopenaeus vannamei (LvHemolin). Sequence analysis showed that LvHemolin shares high similarity with insect Hemolins and is mainly composed of seven immunoglobulin (Ig) domains which form a 'horseshoe' tertiary structure. Tissue distribution analysis demonstrated that LvHemolin mainly expressed in stomach, gill, epithelium and pyloric cecum of L vannamei. After challenge with pathogens or stimulants, expression of LvHemolin was significantly up-regulated in both gill and stomach. Agglutination analysis demonstrated that recombinant LvHemolin protein purified from Escherichia coli could accelerate the agglutination of Vibrio parahaemolyticus, E. coil, Staphylococcus aureus, and Bacillus subtilis in the presence of Ca2+. To verify the immune function of LvHemolin in vivo, shrimps were injected with gene-specific dsRNA, followed by challenge with white spot syndrome virus (WSSV) or V. parahaemolyticus. The results revealed that silence of LvHemolin could increase the cumulative mortalities of shrimps challenged by pathogens and increase the WSSV copies in shrimp tissues. These suggested that Hemolin could play an important role in shrimp innate immune defense against bacterial and viral infections. (C) 2014 Elsevier Ltd. All rights reserved.