School of Animal Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, 111 University Avenue, Muang, Nakhon Ratchasima 30000, Thailand.
Comp Biochem Physiol B Biochem Mol Biol. 2013 Oct;166(2):148-56. doi: 10.1016/j.cbpb.2013.07.011. Epub 2013 Aug 9.
Fatty acid delta-6 desaturase (fads2)-like gene from Nile tilapia (Oreochromis niloticus) was characterized and designated as oni-fads2. The Oni-FADS2 showed the typical structure of microsomal FADS2. The presence of oni-fads2 transcripts in unfertilized eggs demonstrated the maternal role of Nile tilapia in providing the oni-fads2 transcript in their eggs. In addition, the expression of oni-fads2 was detectable in embryos throughout the hatching stage. Real-time reverse transcription-PCR revealed that oni-fads2 was expressed at a high level in all the brain regions, liver, and testis. Recombinant yeast (RY) was generated by transformation of Saccharomyces cerevisiae with the plasmid containing oni-fads2 driven by the Gal1 promoter (pYoni-fads2). The conspicuous expression of RY was detectable by RT-PCR after induction with galactose for 24h. When RY was induced with galactose, it exhibited 39% and 7% of delta-6 desaturase (∆6) activity toward C18:2n6 and C18:3n3, respectively. Additionally, it displayed 4% of delta-5 desaturase (∆5) activity toward C20:3n6, indicating that Oni-FADS2 had ∆5 and ∆6 bifunction.
尼罗罗非鱼（Oreochromis niloticus）脂肪酸 delta-6 去饱和酶（fads2）样基因的特性及其命名为 oni-fads2。Oni-FADS2 具有典型的微粒体 FADS2 结构。未受精卵中 oni-fads2 转录本的存在表明尼罗罗非鱼在其卵子中提供 oni-fads2 转录本的母性作用。此外，在孵化阶段的整个胚胎中都可以检测到 oni-fads2 的表达。实时逆转录-PCR 显示 oni-fads2 在所有脑区、肝脏和睾丸中均高水平表达。通过含有 Gal1 启动子驱动的 oni-fads2 的质粒转化酿酒酵母（RY），生成重组酵母（RY）。用半乳糖诱导 24 小时后，通过 RT-PCR 可检测到 RY 的明显表达。当 RY 用半乳糖诱导时，它对 C18:2n6 和 C18:3n3 的 delta-6 去饱和酶（∆6）活性分别为 39%和 7%。此外，它对 C20:3n6 的 delta-5 去饱和酶（∆5）活性为 4%，表明 Oni-FADS2 具有 ∆5 和 ∆6 双功能。
