Nayak Madhusmita, Pradhan Avinash, Giri Shiba Shankar, Samanta Mrinal, Konkimalla V Badireenath, Saha Ashis
Division of Fish Nutrition and Physiology, ICAR-Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar, Odisha, India.
Division of Fish Health Management, ICAR-Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar, Odisha, India.
Comp Biochem Physiol B Biochem Mol Biol. 2018 Mar;217:27-39. doi: 10.1016/j.cbpb.2017.12.004. Epub 2017 Dec 9.
Fatty acid desaturase (Fads) and elongase (Elovl) are two important enzymes involved in the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs) in fishes. Silver barb (Puntius gonionotus) is considered a promising medium carp species for freshwater aquaculture in Asia. Earlier, Δ6 fads cDNA was characterized to understand the molecular mechanism of LC-PUFA biosynthesis in this species. In the present study elovl5-like elongase full-length cDNA was cloned and characterized by RACE (rapid amplification of cDNA ends), and analyzed its basal expression in various organs/tissues by quantitative real time PCR (qRT-PCR) assay. Differential expression of elovl5 cDNA in various tissues following replacement of fish oil (FO) with linseed oil (LO) in the diet also studied. The full length cDNA sequence of silver barb elovl5-like elongase consisted of 1853bp, including an open reading frame (ORF) of 876bp encoding a precursor protein of 291 amino acids possessing the entire characteristic features of Elovl protein. The elovl5 transcript was constitutively expressed in all the tissues examined: muscle, liver, brain, kidney, skin, intestine, gill and eye. The expression of elovl5 gene was upregulated, whereas the serum biochemical constituents were either remain unchanged or lowered following replacement of FO with LO in the diets. We report for the first time, an in silico 3D structure model of elongase protein from silver barb. All these findings may contribute to a better understanding the potential regulatory mechanisms involved and may be useful for enhancing endogenous LC-PUFA production in silver barb.
脂肪酸去饱和酶（Fads）和延长酶（Elovl）是鱼类中参与长链多不饱和脂肪酸（LC-PUFAs）生物合成的两种重要酶。鲮鱼（Puntius gonionotus）被认为是亚洲淡水养殖中有前景的中型鲤鱼品种。此前，已对Δ6 fads cDNA进行了表征，以了解该物种中LC-PUFA生物合成的分子机制。在本研究中，通过RACE（cDNA末端快速扩增）克隆并表征了elovl5样延长酶的全长cDNA，并通过定量实时PCR（qRT-PCR）分析了其在各种器官/组织中的基础表达。还研究了用亚麻籽油（LO）替代饲料中的鱼油（FO）后，elovl5 cDNA在各种组织中的差异表达。鲮鱼elovl5样延长酶的全长cDNA序列由1853bp组成，包括一个876bp的开放阅读框（ORF），编码一个291个氨基酸的前体蛋白，具有Elovl蛋白的全部特征。elovl5转录本在所有检测的组织中组成性表达：肌肉、肝脏、大脑、肾脏、皮肤、肠道、鳃和眼睛。用LO替代饲料中的FO后，elovl5基因的表达上调，而血清生化成分要么保持不变，要么降低。我们首次报道了鲮鱼延长酶蛋白的计算机三维结构模型。所有这些发现可能有助于更好地理解其中潜在的调控机制，并可能有助于提高鲮鱼体内LC-PUFA的产量。
