3 讨论 - 水产学报.doc

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 重新补充作者及单位信息，此次修改后不能作添加等修改 范武江，李思发*，王兵，孟庆辉 （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） 摘要：为探讨尼罗罗非鱼(Oreochromis niloticus)新吉富品系、萨罗罗非鱼(Sarotherodon melanotheron)及其杂交子代(Oreochromis niloticus♀× Sarotherodon melanotheron♂)IGF-I基因结构差异，研究IGF-I基因与三种基因型罗非鱼耐盐性能差异之间的的关系，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）），萨罗罗非鱼在E133位发生Ala/Pro氨基酸残基替换，与莫桑比克罗非鱼和画眉罗非鱼一致，推测IGF-Ib基因E区选择性剪切与三种罗非鱼耐盐性能差异有关。 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–I b；cDNA；克隆 CLONING AND SEQUECNCING OF IGF-Ib 3`cDNA IN OREOCHROMIS NILOTICUS , SAROTHERODON MELANOTHERON AND THEIR HYBRID Fan Wu-jiang, Li Si-fa,Wang Bing,Meng Qing-hui Key Laboratory of Aquatic Genetic Resources and Aquacultural Ecosystem Certificated by the Ministry of Agriculture,Shanghai Ocean University, Shanghai 201306, China 补充作者及单位的英文信息 Abstract：Nele tilapia(Oreochromis niloticus NewGifts，ON ), black-chined 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 were demonstrated to be the IGF-Ib gene cDNAs with length of 1076bp,1075bp and 1079bp respectively and comprising of a stop codon, a 546bp 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 composed of signal peptide, mature peptide（including conserved B,C,A and D domain consisting of 29-aa,10-aa,21-aa and 8-aa respectively）and E domain of 70aa. Results of the predicted secondary structures of IGF-Ib 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 domain