【摘要】 过氧化物酶体增殖物激活受体(PPAR)是核激素受体超家族成员之一,分α,β,γ3个亚型,PPAR具有多种生物学效能,对其基因进行研究将有助于揭示草食性鱼类对营养物利用规律及其机制.通过简并引物克隆草鱼(C tenopharyngodon idellus)PPAR基因cDNA核心序列,应用3′RACE技术扩增该序列的3′末端序列,并对其进行序列分析,最后用荧光定量PCR方法比较草鱼肝脏、脑、脾脏、肌肉、脂肪和心脏的PPARα、PPARβ和PPARγ基因mRNA相对表达水平.序列分析结果表明,草鱼PPARα、PPARβ和PPARγ基因cDNA核心序列片段大小为631 bp,604 bp和651 bp,分别编码210、201和217个氨基酸,PPARγ经3′RACE后共获得大小为1331 bp的片段,编码337个氨基酸.草鱼与鲤鱼(Cyprinus carpio)、斑马鱼(Danio rerio)、鲈鱼(Lateolabrax japonicus)等鱼类PPAR氨基酸序列同源性很高,为71.4%~96.1%;与人(Homo sapiens)、大鼠(Rattus norvegicus)、小鼠(Mus musculus)、牛(Bos taurus)等哺乳动物PPAR氨基酸序列的同源性也较高,为65.0%~77.6%;与非洲爪蟾(Xenopus laevis)等两栖动物PPAR氨基酸序列的同源性约为67.0%.荧光定量PCR结果表明,草鱼PPARα于肝脏,PPARβ于肝脏、肌肉和心脏,PPARγ于肝脏的表达相对较高.相同物种不同PPAR亚型的同源性较低,而不同物种同型PPAR同源性很高,反映了不同亚型在结构上的差异,这与其在功能上的差异是相一致的.更多还原

【Abstract】 Peroxisome proliferator activated receptor(PPAR) is a member of the family of nuclear hormone receptors and there are three isotypes-α,β and γ.PPAR has many biological effects,and the research on PPAR will help reveal the rule and its mechanism about the use of nutrients of the herbivorous fish.PCR using the degenerated primers,yielded three cDNA fragments of PPAR α,PPAR β and PPAR γ from the liver of grass carp,and the cDNA fragment of PPAR γ was completed by 3′RACE.The grass carp PPAR α,PPAR β and PPAR γ cDNAs were 631bp,604bp and 651bp in length,encoding 210,201 and 217 amino acids,respectively.PPAR γ cDNA added 3′RACE was 1 331bp,encoding 337 amino acids.Search results of the BLAST protein database revealed that the deduced amino acid sequences of grass carp PPAR were highly(71.4%-96.1%) homologous with common carp,zebrafish and Japanese sea bass,were 65.0%-77.6% homologous with those of mammals(including human,mouse,rat and cow) and were 67.0% homologous with amphibians,like African clawed frog.Finally,we compared the relative expression level of mRNA of PPAR α,PPAR β and PPAR γ in liver,brain,spleen,muscle,fat and heart of grass carp by real-time PCR.The result suggested that PPAR α higher expressed in liver,PPAR β in liver,muscle and heart,and PPARγ in liver.Different subtypes of PPAR in the same species with low homology,and the same type of PPAR in the different species with high homology,this results reflect the differences between the different subtypes in structure,which Consistent with the difference in function.更多还原