大鳍鳠IgL2型基因cDNA的克隆及表达分析  

Molecular cloning and expression analysis of the immunoglobulin light chain 2 isotype gene cDNA in Mystus macropterus Bleeker

作　　者：李春涛[1] 蒋自立[1] 曾伯平[1] 张其中[2] 

机构地区：[1]遵义师范学院生命科学学院,贵州遵义563000 [2]暨南大学水生生物研究所,广州510632

出　　处：《淡水渔业》2014年第1期20-25,58,共7页Freshwater Fisheries

基　　金：国家自然科学基金项目(31170474);黔科合J字LKZS[2012]20号;黔科合人才团队[2012]4004

摘　　要：应用RT和RACE-PCR方法获得大鳍鳠(Mystus macropterus Bleeker)免疫球蛋白轻链(IgL)2型基因cDNA序列,分析了该基因在组织中的表达。该基因cDNA全长为929 bp,包含5'非编码区43 bp,3'非编码区159 bp,开放阅读框720 bp,编码239个氨基酸。编码的氨基酸序列分为可变区(VL)和恒定区(CL)。系统进化树分析显示,大鳍鳠IgL蛋白质序列与斑点叉尾IgL 2型(G型)合为一支,与其它硬骨鱼类IgL2型聚为一簇。组织分布研究表明,大鳍鳠IgL2基因表达量在脾脏最高,其次是鳃和头肾,这明显与大鳍鳠IgL3型基因表达方式不同。注射嗜水气单胞菌后,大鳍鳠IgL2基因转录表达量在脾脏、鳃和头肾都随时间发生变化。IgL2基因转录表达量在脾脏4 d就到达高峰,在鳃1 d就达到峰值。这些应答规律与IgL3基因差异显著,推测,IgL2的表达主要参与鳃、肠和皮肤主导的粘膜免疫。RT-PCR and Rapid Amplification of cDNA Ends （ RACE） PCR was used to amplify cDNA of immunoglobulin light chain 2 isotype （IgL2） gene from catfish.IgL2 in Myts us macropterus had 929 nucleotides, including 5′-UTR of 43 nucleotides, 3′-UTR of 159 nucleotides and an open reading frame with 720 nucleotides encoding a peptide of 239 amino acids.The deduced amino acid sequence consisted of an constant region （ CL） and a variable domain （ VL）.Phylogenetic tree based on some fish IgL amino acids showed that IgL 2 in M.macropterus was clustered closely with that （ G ） of I.Punctatus.The study on tissue distribution showed that IgL 2 mRNA expression of M.macropterus was mainly detected in spleen,gill and head kidney and increased significantly in these tissues after injection of Aeromonas hydrophila.IgL2 tran-scription level peaked on the4 th day in spleen and on the ist day in gill after bacterin immunization , which was different from that of IgL3 in M.macropterus.The result indicated that IgL2 played a critical role in immunity interaction of mucosa-associated lymphoid tissue （ MALT） in M.macropterus.

关 键 词：大鳍鳠( Mystus macropterus) 克隆 表达 

分 类 号：S917.4[农业科学—水产科学]