尼罗罗非鱼、萨罗罗非鱼及其杂交子代胰岛素样生长因子(IGF-Ⅰb)基因3′cDNA末端克隆及序列分析  

Cloning and sequencing of IGF-Ⅰb 3'cDNA in Oreochromis niloticus,Sarotherodon melanotheron and their hybrid

作　　者：范武江[1] 李思发[1] 王兵[1] 孟庆辉[1] 

机构地区：[1]上海海洋大学农业部水产种质资源与利用重点开放实验室,上海201306

出　　处：《水产学报》2010年第4期489-499,共11页Journal of Fisheries of China

基　　金：罗非鱼产业技术体系(新D-8002-09-0055);公益性行业(农业)科研专项:罗非鱼大规格鱼种规模化培育与生态养殖技术研究(nyhyzx07-044-01);国家科技支撑计划专题:耐盐罗非鱼新品种选育(2006BAD01A1203)

摘　　要：为探讨尼罗罗非鱼、萨罗罗非鱼及其杂交子代(Oreochromis niloticus ♀× Sarotherodon melanotheron ♂)IGF-Ⅰ基因结构差异,研究IGF-Ⅰ基因与此3种基因型罗非鱼耐盐性能差异之间的关系,通过3′-RACE的方法,从鳃的总RNA分别获得其IGF-Ⅰb基因的部分cDNA序列,长度分别为1076bp、1075bp和1079bp,包含完整的开放阅读框(ORF)546bp、一个终止密码及含polyA信号的3′UTR;ORF编码182个氨基酸,包括信号肽(44aa),成熟肽B区(29aa)、C区(10aa)、A区(21aa)、D区(8aa)及编码70aa的E区,二级结构为混合类型;与其他脊椎动物IGF-Ⅰb序列的序列相似度达75.8%～100%;成熟肽A、B区高度保守,C区第82位后缺失2aa,E区第131位和159位分别缺失3aa和1aa;萨罗罗非鱼在E133位发生Ala/Pro氨基酸残基替换,与耐盐性强的莫桑比克罗非鱼和画眉罗非鱼一致,推测IGF-Ⅰb基因E区选择性剪切与3种罗非鱼耐盐性能差异有关。Aiming at exploring the sequence differences of IGF-Ⅰ gene of Nile tilapia（Oreochromis niloticus NewGifts,ON）,black-chin tilapia（Sarotherodon melanotheron,SM） and their First Generation of Hybrid（HB）,investigating the relationships between the great differences of salt-resistant property among the three genotypes,we cloned partial cDNA fragments of insulin-like growth factor Ⅰ（IGF-Ⅰ） from gill extracts through rapid amplification of 3＇ cDNA ends（3＇RACE）methods.The results demonstrated to be the IGF-Ⅰb gene cDNAs with length of 1076 bp,1075 bp and 1079 bp respectively and comprising of a stop codon,a 546 bp open reading frame（ORF） encoding a 182 amino acid peptides（aa）,and 3＇-untranslated regions（3＇-UTR）.The deduced amino acid sequence of IGF-Ⅰb precursor is composed of signal peptide,mature peptide（including conserved B,C,A and D domains consisting of 29-aa,10-aa,21-aa and 8-aa respectively）and E domain of 70aa.Results of the predicted secondary structures were typed as＂mixed patterns＂.The results of multiple alignments showed highly homologous with 75.8% to 100% amino acid identity.The B and A domains are highly conserved in all of the allied species.There are 2aa-deletion between No.82 and 83 sites in C domain,3aa and 1aa-deletion next to NO.131 and No.159 site,respectively.Ala/Pro substitution occurred at No.133 of E domain of black-chin tilapia compared with ON and HB,which is identical to Oreochromis mossambicus and Oreochromis urolepis hornorum.We presumed that the differences of saltresistant property of ON,SM and HB may be due to the alterative splicing of the IGF-Ⅰ E domain.

关 键 词：尼罗罗非鱼 萨罗罗非鱼 杂交子代 胰岛素样生长因子-Ⅰb cDNA 克隆 

分 类 号：Q785[生物学—分子生物学] S917[农业科学—水产科学]