Gene structure, recombinant expression and functional characterization of grass carp leptin
Gene structure, recombinant expression and functional characterization of grass carp leptin
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DOI：
10.1016/j.ygcen.2009.10.009
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发表时间：
2010-03-01
影响因子：
2.7
通讯作者：
Lai, Kaaseng
中科院分区：
文献类型：
--
作者：
Li, Guan-Gui;Liang, Xu-Fang;Lai, Kaaseng
瘦素是调节哺乳动物摄食、能量消耗和生殖的一种重要激素，但有关其在硬骨鱼中的作用的信息仍然很少。本研究对草鱼(Ctenophyngodon Idellus)和鲤鱼(Hypophthalmichthys Molitrix)瘦素的基因结构进行了研究。将重组草鱼瘦素(RGC-LEP)在大肠杆菌中表达、纯化，并用质谱仪进行鉴定。草鱼腹膜注射RGC-LEP后第一天出现明显的厌食效应，但随后几天没有明显的厌食效应。在整个实验期间，瘦素组(LEP组)和配对喂养组(PF组)的体重没有差异。用实时荧光定量聚合酶链式反应进一步表征急性和慢性对与摄食量、能量消耗、脂肪代谢和消化相关的关键基因表达的影响。相应地，注射后第1天神经肽Y(NPY)、硬脂酰辅酶A脱饱和酶1(SCD 1)和脂蛋白脂酶(LPL)的mRNA水平显著降低，解偶联蛋白2(UCP2)、胆盐活化脂肪酶(BSal)和脂肪酸延伸酶(ELO)的mRNA水平显著升高。与外源瘦素对哺乳动物瘦素基因表达的下调不同，RGC-LEP处理后第1天，草鱼瘦素基因的表达水平提高了5.76倍。我们的结果表明，瘦素对草鱼摄食量、能量消耗和脂肪代谢的调节具有急性作用，但这种作用可以通过目前尚不清楚的机制迅速抵消。(C)2009 Elsevier Inc.保留所有权利。
Leptin is an important hormone for the regulation of food intake, energy expenditure and reproduction in mammals, but information regarding its role in teleosts remains scant. In the present study, the gene structures of grass carp (Ctenopharyngodon idellus) and silver carp (Hypophthalmichthys molitrix) leptins were characterized. Recombinant grass carp leptin (rgc-LEP) was expressed in Escherichia coli and purified, and identified by mass spectrometric analysis. A strong anorexic effect on food intake was observed in grass carp on the first day after intraperitoneal (IP) injection of rgc-LEP, but not during the following days. Body weight of the leptin group (LEP group) and the pair-fed group (PF group) showed no difference throughout the experimental period. The acute and chronic effects on the expression of key genes correlating to food intake, energy expenditure, lipid metabolism and digestion were further characterized by real-time PCR. Accordingly, the mRNA levels of neuropeptide Y (NPY), Stearoyl-CoA desaturase 1 (SCD1) and lipoprotein lipase (LPL) were significantly reduced whereas the mRNA levels of uncoupling protein 2 (UCP2), bile salt-activated lipase (BSAL) and fatty acid elongase (ELO) were significantly elevated on the first day after injection. No effect on the expression of these genes (except LPL) was observed on day 13. In contrast to the down-regulation by exogenous leptin in mammals, the mRNA level of grass carp leptin was elevated 5.76-fold on the first day after rgc-LEP treatment. Our results suggest that leptin has an acute effect on the regulation of food intake, energy expenditure and lipid metabolism in grass carp, but the effect can be rapidly counteracted through mechanisms that are currently unknown. (C) 2009 Elsevier Inc. All rights reserved.