缢蛏C型凝集素基因ScCTL-2的序列分析及凝菌活性  

Sequence analysis and bacterial agglutination of C-type lectin gene ScCTL-2 in Sinonovacula constricta

作　　者：蓝天一 牛东红[1] 刘晓军 彭茂潇 李家乐[1] LAN Tianyi;NIU Donghong;LIU Xiaojun;PENG Maoxiao;LI Jiale(Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources,Ministry of Education,Shanghai Ocean University, Shanghai 201306,China)

机构地区：[1]上海海洋大学省部共建水产种质资源发掘与利用教育部重点实验室,上海201306

出　　处：《上海海洋大学学报》2019年第1期20-28,共9页Journal of Shanghai Ocean University

基　　金：国家高技术研究发展计划(2012AA10A400-3);国家自然科学基金(31472278);上海知识服务平台(ZF1206)

摘　　要：为研究缢蛏C型凝集素基因ScCTL-2的结构和功能特点,克隆了该基因的全长序列,并对其mRNA的表达模式以及重组蛋白的凝菌活性进行研究。结果显示,ScCTL-2的cDNA全长2 194 bp,共编码630个氨基酸,其氨基酸序列拥有4个C型凝集素糖识别结构域和1个N端跨膜区,这一特殊的序列结构不同于任何一种已知的C型凝集素。基因mRNA在健康缢蛏肝胰腺中的表达量显著高于其他组织,在鳃中的表达量次之,而在其余组织中的表达量没有显著性差异;金黄色葡萄球菌与鳗弧菌感染能够显著上调ScCTL-2在缢蛏血细胞中的表达。ScCTL-2的重组蛋白凝菌实验显示:在Ca^(2+)存在的情况下,rScCTL-2能够对实验所采用的金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌、藤黄微球菌和酿酒酵母均产生明显的凝集反应;当溶液中不存在Ca^(2+)时,凝集反应几乎不能发生,意味着rScCTL-2的凝菌活性是严格Ca^(2+)依赖的。研究表明,ScCTL-2可能是一种新的无脊椎动物C型凝集素类型,它具有无脊椎动物C型凝集素普遍具备的免疫活性,可能在缢蛏的免疫中具有重要作用。C-type lectins are a superfamily of Ca^2+-dependent carbohydrate-binding proteins that play crucial roles in invertebrate immunity. A novel C-type lectin gene( ScCTL-2) was identified in razor clam Sinonovacula constricta. Sequence analysis showed that the full length ScCTL-2 contains a 1893 bp ORF encoding 630 amino acid polypeptide with four CTLD( C-type lectin domain) and a N-terminal transmembrane region. The special structure of ScCTL-2 protein revealed that ScCTL-2 is perhaps a new group of invertebrate C-type lectins. The ScCTL-2 was expressed in almost all tissues,with highest expression in hepatopancreas and the second highest expression in gill. Bacterial stimulation up-regulated ScCTL-2 expression in hemocytes. The spatial-and temporal-specific expression patterns of ScCTL-2 suggest it may be an immune-related gene in razor clam. Recombinant protein( r ScCTL-2) displayed a broad bacterial agglutination spectrum,and the agglutinate activity was strictly Ca^2+-dependent. It could agglutinate all the experimental bacteria only if Ca^2+existed. The results suggest ScCTL-2 is a novel gene possessing common immune characteristics of invertebrate C-type lectins.

关 键 词：缢蛏 C型凝集素 凝菌 

分 类 号：S197[农业科学—农业基础科学]