作　　者： ; ; ; ; ;

机构地区： 中国水产科学研究院珠江水产研究所

出　　处： 《农业生物技术学报》 2012年第2期171-180,共10页

摘　　要： 胰岛素样生长因子(insulin-like growth factors,IGFs)在鱼类的生长、发育过程中起重要作用。本研究克隆了荷那龙罗非鱼(Oreochromis hornorum)两种胰岛素样生长因子(IGF)基因,并采用半定量RT-PCR方法检测了两种基因在不同组织中的表达情况。以荷那龙罗非鱼肝脏总RNA为模板,RT-PCR结合3'RACE与5'RACE法扩增IGF-Ⅰ与IGF-Ⅱ的cDNA。扩增片段插入pMD-T载体并测序。序列分析表明:IGF-Ⅰ总长1305bp;IGF-Ⅱ总长1091bp。其推测氨基酸序列都具有胰岛素样生长因子基因的典型特征结构,分别包括信号肽和B、C、A、D、E5个区域,并具有6个保守的半胱氨酸,但它们之间推测氨基酸全序列的同源性较低,为26%。正常生理条件下,两种IGF在所有被检测组织中均有表达。IGF-Ⅰ在肝脏、肌肉和性腺中表达量较高,在肾脏中表达量最低;IGF-Ⅱ在肾、胃、肠、脾、垂体中表达量较高,在肌肉中表达量最低。在所有被检测组织中,IGF-Ⅱ的表达量均高于IGF-Ⅰ的表达量,但二者的表达量只有在肠、脾、胃、肾和垂体中具有显著性差异(P<0.05)。雌雄个体中除脾、胃、肾、垂体外,IGF-Ⅰ在雌性中的其它组织表达均低于雄性,其中雄性个体中肌肉组织IGF-Ⅰ的表达水平显著高于雌性个体(P<0.05);IGF-Ⅱ在雌雄个体相同组织间的表达水平比较差异均不显著。本研究有助于进一步了解荷那龙罗非鱼的生长调节机制和更好地理解鱼类IGFs的生理功能。 Insulin-like growth factors（IGFs） Ⅰ and Ⅱ（IGF-Ⅰ and IGF-Ⅱ） play important roles in fish growth and development.In this study,cDNAs of both IGF subtypes were cloned and sequenced from zanzibar tilapia（Oreochromis hornornum）,the expression patterns of the two IGF were detected using semi-quantitive RT-PCR.Total RNAs were isolated from liver of zanzibar tilapia.The cDNAs encoding IGF-Ⅰ and IGF-Ⅱ were amplified by RT-PCR,3＇RACE and 5＇RACE.The amplified cDNA fragments were inserted into pMD-T vector.Sequence analysis revealed that the IGF-Ⅰ and IGF-Ⅱconsisted of 1 305 and 1 091 bp,respectively.They all had the characteristic landmarks of IGF,for example,they all possessed signal peptide and B,C,A,D and E domains and six cysteine residues,but their features were distinctly different from each other,the overall deduced amino acid sequence identity between IGF-Ⅰand IGF-Ⅱ was rather low（26%）.Under normal physiological conditions,both IGF-Ⅰ and IGF-Ⅱ were present in all tissues examined.IGF-Ⅰwas most highly expressed in liver,muscle and gonad but lowly expressed in kidney.IGF-Ⅱwas most highly expressed in kidney,stomach,intestine,spleen and pituitary,but low in muscle.The mRNA levels of IGF-Ⅱwere higher than that of IGF-Ⅰ in all tissues tested,but significantly difference（P0.05） only observed in intestine,spleen,stomach,kidney and pituitary.IGF-Ⅰ expressions in females were lower in most tissues examined than those in males except for in spleen,stomach,kidney and pituitary.But significant difference existed in muscle（P0.05）.No significant difference was found in IGF-Ⅱexpression in all the tissues of male and female zanzibar tilapia.This observation can contribute to further investigation of growth regulation of zanzibar tilapia,and the results will give us a better understanding for the physiologyical role of IGFs in fish.

关 键 词： 荷那龙罗非鱼 胰岛素样生长因子 克隆 组织表达

领　　域： [农业科学] [农业科学]