摘要
转铁蛋白(Transferrin,Tf)功能广泛,不仅参与机体内铁离子的运输和代谢,还在细胞呼吸、细胞生长和增殖中起重要作用,而且它具有抗菌杀菌的功能。研究从草鱼肝肾全长cDNA文库中克隆得到草鱼转铁蛋白基因(CtTf),该基因全长cDNA5′非编码区包含31bp,最大开放阅读框为2025bp,编码674个氨基酸,3′非编码区为266bp。研究使用了Signal P、SMART等在线软件对草鱼转铁蛋白全长cDNA的分子特征进行预测,结果显示CtTf编码的蛋白质N-端有1个由15个氨基酸残基组成的信号肽,第24—334个和第338—665个氨基酸为2个保守的结构域,二者同源率为31%。与其他物种的转铁蛋白类似,草鱼转铁蛋白每个结构域包含4个铁离子结合位点,它们在两个结构域中的位置相对保守,除了这8个铁离子结合位点外,还存在多个完全保守的氨基酸位点。草鱼转铁蛋白与人及其他物种有很高的同源性,与其他鲤科鱼类的同源性为65%—73%;与海洋鱼类同源性为43%—50%;与两栖、爬行、鸟类、哺乳类的同源性为40%—42%。系统进化树也显示草鱼转铁蛋白基因与斑马鱼和鲤鱼的亲缘关系最近。RT-PCR的实验结果表明,在草鱼肝、肠、肾、脾、心、肌肉、鳃和脑8种组织中,草鱼转铁蛋白基因在肝中的表达量最高,其次为脾和肠,在鳃和脑中有痕量表达。
Transferrin has diverse functions that not only participates in the transportation and metabolism of organism iron ions, but also plays key effect in cellular respiration, cellular growth and proliferation, moreover, it has the antimicrobial bactericidal bioactivity. This study screened and cloned Ctenopharyngodon idellus transferrin gene （CtTf） from grass carp cDNA library. This full CtTf sequence was 2322bp and contained a 5’untranslated region of 31bp and a 3’untranslated region of 266bp. The CtTf ORF contained 2025bp which could code a 674 amino acids peptide. Forecasting molecular characteristics of this CtTf by the online software, the result showed that N-lobe of grass carp transferrin was a signal peptide of 15 amino acides. This gene was composed of two similar domains, and the identity of the two domains was 31%. Similarly with the transferrin in other animals, grass carp transferrin has four iron ion binding sites in each domain, and positions of them were relatively conservative. There were several other conservative sites besides the eight iron ion binding sites in the domains. Grass carp transferrin had the high homology with human and other species, such as it shared the identity of about 65%—73% with other Cyprinid fish, 43%—50% with marine fish, and 40%—42% with amphibians, reptiles, aves and mammals. Phylogenetic tree analysis revealed that grass carp transferrin gene shared the highest homology with zebra fish and cyprinoid. The result of RT-PCR experiment indicted that, among the liver, intestine, kidney, spleen, heart, muscle, gill and brain of grass carp, the transferrin gene had the highest expressional level in liver, the spleen and intestine ranked secondly, which had trace amount in gill and brain.
出处
《水生生物学报》
CAS
CSCD
北大核心
2010年第1期51-56,共6页
Acta Hydrobiologica Sinica
基金
江西省重点科技攻关项目(No20061B0260301)资助
关键词
草鱼
转铁蛋白
表达
Grass carp
Transferrin
Expression
