A novel C-type lectin from bay scallop Argopecten irradians (AiCTL-7) agglutinating fungi with mannose specificity
A novel C-type lectin from bay scallop Argopecten irradians (AiCTL-7) agglutinating fungi with mannose specificity
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一种来自海湾扇贝海湾扇贝的新型 C 型凝集素 (AiCTL-7)，具有甘露糖特异性凝集真菌
DOI：
10.1016/j.fsi.2011.01.005
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发表时间：
2011-03-01
影响因子：
4.7
通讯作者：
Song, Linsheng
中科院分区：
文献类型：
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作者：
Kong, Pengfei;Wang, Lingling;Song, Linsheng
C型凝集素是一个超家族的蛋白质，可以通过识别碳水化合物结合病原体相关分子模式（PAMP）和微生物，因此它们直接参与先天防御机制，作为对感染的急性期反应的一部分。本研究采用表达序列标签（EST）分析和cDNA末端快速扩增（RACE）技术，从海湾扇贝中克隆了一个新的C型凝集素（AiCTL-7）的cDNA。AiCTL-7全长cDNA为651 bp，开放阅读框为525 bp，编码15个氨基酸的信号肽和174个氨基酸的碳水化合物识别结构域（CRD），其EPD和WSD基序取代了脊椎动物的EPN和WND基序，用于确定碳水化合物结合特异性和构建脊椎动物的Ca 2+结合位点2。AiCTL-7 CRD的氨基酸序列不仅与软体动物C型凝集素的CRD同源，而且与鱼类凝集素的CRD同源。AiCTL-7的mRNA主要在健康扇贝的肝胰腺组织中表达，在肾脏、性腺、血细胞、心脏和闭壳肌中也有少量表达。经巴斯德毕赤酵母（Pichia pastoris）GS115和革兰氏阴性菌鳗利斯特氏菌（Listonella anguillarum）攻击后，AiCTL-7在肝胰腺和血细胞中的相对表达量显著上调。在大肠杆菌中重组表达了AiCTL-7的CRD，重组蛋白（rAiCTL-7）能显著凝集巴斯德毕赤酵母（P. pastoris），且这种凝集作用可被D-甘露糖抑制，而不被D-半乳糖或β-1，3-葡聚糖抑制。rAiCTL-7对鳗弧菌没有明显的凝集活性。这些结果表明，AiCTL-7作为扇贝先天免疫系统中重要的模式识别受体（PRR）参与了扇贝对微生物入侵的原始急性期反应。(C)2011爱思唯尔有限公司保留所有权利。
C-type lectins are a superfamily of proteins that can bind pathogen-associated molecular patterns (PAMPs) and microorganisms through the recognition of carbohydrates, thus they are directly involved in innate defense mechanisms as part of the acute-phase response to infection. In this study, the cDNA of a novel C-type lectin (designated as AiCTL-7) was cloned from bay scallop Argopecten irradians by expression sequence tag (EST) analysis and rapid amplification of cDNA ends (RACE) approach. The full-length cDNA of AiCTL-7 was of 651 bp containing a 525 bp open reading frame which encoded a signal peptide of 15 residues and a conserved carbohydrate-recognition domain (CRD) of 174 residues with the EPD and WSD motifs instead of the invariant EPN and WND motifs for determining the carbohydrate-binding specificity and constructing Ca2+-binding site 2 in vertebrates. The deduced amino acid sequence of AiCTL-7 CRD shared homology not only with the CRDs of C-type lectins in mollusks, but also with the fish lectin CRDs. The mRNA transcripts of AiCTL-7 were mainly detected in the tissue of hepatopancreas and also marginally detectable in kidney, gonad, hemocytes, heart and adductor of health scallop. After challenge with fungi Pichia pastoris GS115 and Gram-negative bacteria Listonella anguillarum, the relative expression level of AiCTL-7 was up-regulated significantly in hepatopancreas and hemocytes. The CRD of AiCTL-7 was recombined and expressed in Escherichia coli, and the recombinant protein (rAiCTL-7) aggregated P. pastoris remarkably in a Ca2+-dependent manner, and this agglutination could be inhibited by D-mannose, but not by D-galactose or beta-1,3-glucan. However, rAiCTL-7 displayed no obvious agglutinating activity against L anguillarum. These results collectively indicated that AiCTL-7 was involved in the primitive acute-phase response to microbial invasion as an important pattern recognition receptor (PRR) in the innate immune system of scallops. (C) 2011 Elsevier Ltd. All rights reserved.