草鱼脂肪酸去饱和酶和延长酶基因cDNA全序列的克隆与分析  

Molecular cloning and analyzing of fatty acid desaturase and elongase genes in grass carp(Ctenopharyngodon idellus)

作　　者：杜嵇华[1] 梁旭方[1] 程佳齐[1] 朱滔[1] 朱择敏[1] 郁颖[1] 

机构地区：[1]暨南大学生命科学技术学院生物工程学系,广东广州510632

出　　处：《暨南大学学报（自然科学与医学版）》2011年第5期513-520,共8页Journal of Jinan University(Natural Science & Medicine Edition)

基　　金：国家科技部863项目(2007AA09Z437);国家自然科学基金项目(30670367);广东省科技计划项目(2005B20301005);广东省自然科学基金项目(031886)

摘　　要：利用RT-PCR和RACE方法克隆得到草鱼(Ctenopharyngodon idellus)肝脏中控制高不饱和脂肪酸(HU-FA)合成的脂肪酸去饱和酶(FAD)和脂肪酸延长酶(ELO)基因cDNA全序列.结果表明,草鱼FAD基因cDNA全长为1 994 bp,开放阅读框(ORF)为1 332 bp,编码444个氨基酸.编码的蛋白序列包含FAD全部特征结构区,包括3个组氨酸簇、2个跨膜区和1个细胞色素b5结构域,与其他鱼类的FAD氨基酸序列具有63.5%～70.5%的同源性.通过系统树分析,显示其在系统树中与草食性淡水鱼的亲缘关系最近.克隆得到的草鱼ELO的全长cDNA序列1 131 bp,含有876 bp的ORF,编码291个氨基酸.该蛋白序列含有单一的氧化还原中心组氨酸簇、内质网停留信号和多个跨膜区等ELO特征结构,与其他类别ELO氨基酸具有70.6%～89.3%的同源性.系统树分析显示其在系统树中与草食性和杂食性淡水鱼类亲缘关系较近.草鱼FAD和ELO cDNA全序列的获得为今后进一步研究其体内高不饱和脂肪酸合成途径及阐明该途径在不同鱼类中的分子进化机理奠定基础.Full-length cDNAs of fatty acid desaturase （ FAD. ） and fatty acid elongase （ ELO）, which were involved in the biosynthesis of highly unsaturated fatty acids （ HUFA）, were isolated from grass carp （ Ctenopharyngodon idellus）, based on RT-PCR and RACE methods. The FAD cDNA was 1 994 bp, in cluding an ORF of 1 332 bp specifying a protein of 444 amino acids. The protein sequence contained all the characteristics of microsomal fatty acid desaturases, including 3 histidine boxes, 2 transmembrane re- gions, and a eytochrome b5 domain. The deduced amino a^id sequence shared 63.5% -70. 5% identity with other fishes, and the phylogenetic tree showed that it clustered closely with herbivore freshwater fish. The 1 131 bp cDNA of ELO included an 876 bp ORF encoding a 445 amino acid peptide that contained one single histidine box redox centre motif, one canonical ER retention signal and several transmembrane regions, in line with other fatty acid elongases. The protein sequence had 70. 6% -89. 3% identity with other fishes, and the phylogenetic tree showed that it clustered closely with herbivorous and omnivorous freshwater fish. These results will help study the relationship between their structure and function, and elucidate the HUFA biosynthesis pathway in grass carp.

关 键 词：脂肪酸去饱和酶 脂肪酸延长酶 草鱼 基因克隆 

分 类 号：Q786[生物学—分子生物学]