Diversification of substrate specificities in teleostei Fads2: characterization of Δ4 and Δ6Δ5 desaturases of Chirostoma estor
Diversification of substrate specificities in teleostei Fads2: characterization of Δ4 and Δ6Δ5 desaturases of Chirostoma estor
复制标题
DOI：
10.1194/jlr.m049791
复制
发表时间：
2014-07-01
影响因子：
6.5
通讯作者：
Monroig, Oscar
中科院分区：
文献类型：
--
作者：
Fonseca-Madrigal, Jorge;Navarro, Juan C.;Monroig, Oscar
目前已有的数据表明，硬骨鱼的长链PUFA （LC-PUFA）生物合成能力比其他脊椎动物更多样化。这种多样性主要与远骨脂肪酰基去饱和酶（Fads） 2去饱和酶在进化过程中经历的亚功能化有关。我们之前的研究表明，作为淡水动脉粥样硬化类动物的少数代表之一，Chirostoma estor具有从C-18 PUFA前体生物合成LC-PUFA的能力，这与该物种具有异常高的DHA含量一致。C. estor独特的祖先和LC-PUFA生物合成活性模式使其成为研究硬鱼中LC-PUFA生物合成能力的良好模型。本研究旨在鉴定脂酰延伸酶和去饱和酶的cDNA序列，这是参与LC-PUFA生物合成的关键基因。结果表明，C. estor表达了一个超长链FA (Elovl) 5延长酶和两个具有Delta 4和Delta 6/Delta 5特异性的Fads2去饱和酶，从而使我们得出结论，这三个基因涵盖了C-18 PUFA生物合成LC-PUFA所需的所有酶功能。此外，C. estor Fads2的特异性使我们能够提出Fads2在鱼类谱系中亚功能化的潜在进化模式和机制。
Currently existing data show that the capability for long-chain PUFA (LC-PUFA) biosynthesis in teleost fish is more diverse than in other vertebrates. Such diversity has been primarily linked to the subfunctionalization that teleostei fatty acyl desaturase (Fads) 2 desaturases have undergone during evolution. We previously showed that Chirostoma estor, one of the few representatives of freshwater atherinopsids, had the ability for LC-PUFA biosynthesis from C-18 PUFA precursors, in agreement with this species having unusually high contents of DHA. The particular ancestry and pattern of LC-PUFA biosynthesis activity of C. estor make this species an excellent model for study to gain further insight into LC-PUFA biosynthetic abilities among teleosts. The present study aimed to characterize cDNA sequences encoding fatty acyl elongases and desaturases, key genes involved in the LC-PUFA biosynthesis. Results show that C. estor expresses an elongase of very long-chain FA (Elovl) 5 elongase and two Fads2 desaturases displaying Delta 4 and Delta 6/Delta 5 specificities, thus allowing us to conclude that these three genes cover all the enzymatic abilities required for LC-PUFA biosynthesis from C-18 PUFA. In addition, the specificities of the C. estor Fads2 enabled us to propose potential evolutionary patterns and mechanisms for subfunctionalization of Fads2 among fish lineages.