Yan Jie, Liang Xiao, Cui Yun, Cao Xiaojuan, Gao Jian
College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
College of Fisheries, Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
Biochem Biophys Res Commun. 2018 Jan 22;495(4):2637-2642. doi: 10.1016/j.bbrc.2017.12.123. Epub 2017 Dec 27.
In this study, full-length cDNA sequences of elovl4a and elovl4b from loach Misgurnus anguillicaudatus were cloned. The full-length cDNAs of loach elovl4a and elovl4b were 2423 and 2054bp, encoding 315 and 300 amino acids, respectively. The deduced amino acid sequences of elovl4a and elovl4b in loach both shared the highest identity with those of Danio rerio, whereas lower identity score between loach elovl4a and elovl4b was present. Temporal expression and tissue expression of loach elovl4a and elovl4b were studied by reverse transcriptase PCR. Results of the tissue expression analyses suggested different functions of loach elovl4a and elovl4b. Functional characterizations of loach elovl4a and elovl4b on synthesis of fatty acids, especially elongating C18 polyunsaturated fatty acids (PUFAs) to longer-chain fatty acids, were studied by heterologous expression in Saccharomyces cerevisiae. Loach elovl4a and elvol4b enzymes were able to elongate all fatty acids tested including 18:2n-6, 18:3n-3, 18:3n-6, 20:4n-6 and 20:5n-3. At last, expression levels of the two elovl4 genes of loach fin cells incubated with 18:2n-6 and 18:3n-3 of different concentrations were measured. Expressions of elovl4a and elovl4b of loach fin cells were significantly up-regulated by 18:2n-6 and 18:3n-3. The results obtained here indicated that loach elovl4 could effectively elongate C18 PUFAs. This was a systematic report of elovl4's elongating functions towards C18 and provided an alternative pathway for C20 biosynthesis in fish species.
在本研究中，克隆了泥鳅（Misgurnus anguillicaudatus）中elovl4a和elovl4b的全长cDNA序列。泥鳅elovl4a和elovl4b的全长cDNA分别为2423和2054bp，分别编码315和300个氨基酸。泥鳅中elovl4a和elovl4b推导的氨基酸序列与斑马鱼（Danio rerio）的氨基酸序列具有最高的同一性，而泥鳅elovl4a和elovl4b之间的同一性得分较低。通过逆转录PCR研究了泥鳅elovl4a和elovl4b的时间表达和组织表达。组织表达分析结果表明泥鳅elovl4a和elovl4b具有不同的功能。通过在酿酒酵母中进行异源表达，研究了泥鳅elovl4a和elovl4b在脂肪酸合成，特别是将C18多不饱和脂肪酸（PUFAs）延长为长链脂肪酸方面的功能特性。泥鳅elovl4a和elvol4b酶能够延长所有测试的脂肪酸，包括18:2n-6、18:3n-3、18:3n-6、20:4n-6和20:5n-3。最后，测量了用不同浓度的18:2n-6和18:3n-3孵育的泥鳅鳍细胞中两个elovl4基因的表达水平。泥鳅鳍细胞中elovl4a和elovl4b的表达被18:2n-6和18:3n-3显著上调。此处获得的结果表明泥鳅elovl4可以有效地延长C18 PUFAs。这是关于elovl4对C18的延长功能的系统报告，并为鱼类中C20生物合成提供了一条替代途径。
