Journal of Tropical Oceanography ›› 2009, Vol. 28 ›› Issue (6): 95-102.doi: 10.11978/j.issn.1009-5470.2009.06.095cstr: 32234.14.j.issn.1009-5470.2009.06.095

• Marine biology • Previous Articles     Next Articles

Molecular cloning and analysis of fatty acid desaturase and elongase genes in orange-spotted grouper (Epinephelus coioides)

LI Guan-gui, LIANG Xu-fang, HE Shan, YU Ying, CHEN Xiao-yan, HUANG Bo-yan, CHENG Long-qiu   

  1. College of Life Science and Technology, Jinan University, Shipai, Guangzhou 510632, China
  • Received:2007-12-26 Revised:2008-07-25 Online:2009-12-30 Published:2009-12-12
  • Contact: 梁旭方 E-mail: tliangxf@jnu.edu.cn
  • About author:李观贵(1983—),男,广东茂名人,硕士,主要从事鱼类分子生物学研究。E-mail: liguangui@yahoo.com
  • Supported by:

    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)

Abstract:

Full-length cDNAs of fatty acid desaturase (FAD) and fatty acid elongase (ELO) genes, which were involved in the biosynthesis of highly unsaturated fatty acids (HUFA), were isolated from orange-spotted grouper (Epinephelus coioides) by RT-PCR (reverse transcription polymerase chain reaction) and RACE (rapid-amplification of cDNA ends) methods. The results revealed that the FAD cDNA was 1979 bp, including an ORF (open reading frame) of 1338 bp specified a protein of 445 amino acids. The deduced amino acid sequence shared 66.5%-90.8% identity with other fishes compared to Sparus aurata, Oncorhymchus keta, Cyprinus carpio and Danio rerio. Analysis online showed that its secondary structure was mainly composed helix and extended-beta, and phylogenetic tree revealed that it clustered closely with Sparus aurata and Dicentrarchus labrax. The protein sequence contained all the characteristics of microsomal FADs, including three histidine boxes, two transmembrane regions, and a cytochrome b5 domain. The 1228 bp cDNA of ELO included 885 bp ORF encoding a 294 amino acid peptide that contained a single histidine box redox centre motif, a canonical ER retention signal and multiple transmembrane regions similar with other ELOs. This protein sequence had 71.1%-85.7% identity with Sparus aurata, Oncorhymchus keta, Oreochromis niloticus and Danio rerio. Analysis online showed that its secondary structure was rich with helix and extended-beta, and phylogenetic tree revealed that it clustered closely with Sparus aurata. These results will help future study on the HUFA biosynthesis pathway in orange-spotted grouper.

Key words: fatty acid desaturase, fatty acid elongase, gene cloning, orange-spotted grouper (Epinephelus coioides)