Diurnal expressions of four subtypes of melatonin receptor genes in the optic tectum and retina of goldfish
Diurnal expressions of four subtypes of melatonin receptor genes in the optic tectum and retina of goldfish
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DOI：
10.1016/j.cbpa.2008.09.030
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发表时间：
2009-02-01
影响因子：
2.3
通讯作者：
Ando, Hironori
中科院分区：
文献类型：
--
作者：
Ikegami, Taro;Azuma, Kyoichi;Ando, Hironori
褪黑素受体基因Mel（1a）1.4、Mel（1a）1.7、Mel（1b）和Mel（1c）的4种亚型被认为在金鱼（Carassius auratus）中表达，介导褪黑素的多种生理功能。为了研究它们的组织分布和表达水平的昼夜变化，我们克隆了这些褪黑素受体亚型的部分基因片段，并建立了特异性RT-PCR和定量实时PCR系统。Mel（1a）1.4和Mel（1b）主要在各种神经元和外周组织中表达，而Mel（1a）1.7和Mel（1c）在限制性组织中表达。各亚型基因在视顶盖、间脑、中脑、迷走神经叶、视网膜和脾脏中均有表达。实时荧光定量PCR分析显示，Mel（1a）1.4在视顶盖中以及Mel（1a）1.7和Mel（1b）在视网膜中随时间的变化具有显著性差异。在视网膜中，Mel（1a）1.7和Mel（1b）mRNA的水平显示出昼夜变化，在ZT 24处具有一个峰值。本研究结果表明，四种亚型的褪黑激素受体mRNA的差异分布在神经元和外周组织。然而，视网膜接受脑区和视网膜的所有亚型基因的表达加强了褪黑激素受体在处理视觉信息中的作用。此外，本研究证实了主要亚型基因的昼夜表达，即Mel（1a）1.4在视顶盖和Mel（1a）1.7在视网膜中。(C)2008年爱思唯尔公司All rights reserved.
Four subtypes of melatonin receptor genes (Mel(1a) 1.4, Mel(1a) 1.7, Mel(1b), and Mel(1c)) are considered to be expressed to mediate various physiological functions of melatonin in goldfish (Carassius auratus). To examine their tissue distribution and diurnal changes in expression levels, we cloned partial gene fragments for these melatonin receptor subtypes, and established specific RT-PCR and quantitative real-time PCR systems. Mel(1a) 1.4 and Mel(1b) were predominantly expressed in various neuronal and peripheral tissues, while Mel(1a) 1.7 and Mel(1c) were expressed in the restricted tissues. All subtype genes were expressed in the optic tectum, diencephalon, mesencephalon, vagal lobe, retina and spleen. The real-time PCR analyses showed that significant differences among time were observed for Mel(1a) 1.4 in the optic tectum and for Mel(1a) 1.7 and Mel(1b) in the retina. In the retina, the levels of Mel(1a) 1.7 and Mel(1b) mRNAs showed diurnal changes with one peak at ZT24. The present results show differential distribution of four subtypes of melatonin receptor mRNAs in the neuronal and peripheral tissues. However, the expressions of all subtype genes of the retinorecipient brain regions and retina reinforce the role of the melatonin receptor in processing visual information. Furthermore, the present study demonstrates diurnal expressions of the major subtype genes, i.e. Mel(1a) 1.4 in the optic tectum and Mel(1a) 1.7 in the retina. (C) 2008 Elsevier Inc. All rights reserved.