鲤脂肪酸合成酶基因的克隆与表达分析

摘要

Fatty acid synthase (FASN) as an important enzyme catalyzes the synthesis of fatty acids and the content and activity of FASN have impact on synthesis of fatty acids,fat deposition,and muscle quality.The full-length cDNA of FASN gene was sequenced from common carp Cyprinus carpio by RT-PCR and RACE methods.Full length of the FASN cDNA was found to be 8 927 bp,and open reading flame (ORF) of 7 533 bp encoding 247 amino acids,and the FASN protein had relative molecular weight of 274 145.67 D,and theoretical PI value of 6.10,with fat coefficient of 91.91.The protein shares 75.13％ ～ 95.34％ sequence identity with other fish,and 61.81％ identity with human Homo sapiens.The phylogenetic tree revealed that it clustered closely with herbivorous and omnivorous fieshwater fish,most similar to fish Sinocyclocheilus grahamia.The real-time quantitative PCR revealed that FASN gene was expressed maximally in brain,followed by liver and the minimal in blood.These findings will assist in further understanding of the biosynthesis of FASN in common carp,and enable the methods to be developed for enhancing its production.%脂肪酸合成酶(FASN)是动物体内脂肪酸合成的关键酶.本研究利用逆转录PCR和RACE技术获得鲤Cyprinus carpio FASN全长cDNA序列为8 927bp,开放阅读框7 533bp,编码2 511个氨基酸.FASN蛋白质相对分子量274 145.67D,理论等电点(PI)为6.10.氨基酸同源性分析结果显示:鲤FASN基因与其他鱼类同源性为75.13％～95.34％,与人同源性为61.81％.系统进化树结果显示:鲤FASN氨基酸序列与金线鲃Sinocyclocheilus grahamia聚为一支,同源性最高.实时荧光定量PCR(RT-qPCR)检测结果表明:FASN基因鲤脑组织中表达量最高,肝脏次之,血液中最低.鲤FASN基因的获得为进一步深入研究鲤脂肪酸的合成途径及脂肪发育分子调控机制奠定了基础.