Embryonic and post-embryonic expression of arylalkylamine N-acetyltransferase and melatonin receptor genes in the eye and brain of chum salmon (Oncorhynchus keta)
Embryonic and post-embryonic expression of arylalkylamine N-acetyltransferase and melatonin receptor genes in the eye and brain of chum salmon (Oncorhynchus keta)
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DOI：
10.1016/j.ygcen.2004.01.004
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发表时间：
2004-05-01
影响因子：
2.7
通讯作者：
Urano, A
中科院分区：
文献类型：
--
作者：
Shi, Q;Ando, H;Urano, A
褪黑激素和芳基烷基胺N-乙酰转移酶（AANAT）是褪黑激素合成的限速酶，在脊椎动物昼夜节律生物学中具有特殊的重要性。最近在几种鱼类中鉴定了编码两种AANAT（AANAT（1）和AANAT（2））和两种褪黑素受体亚型（Mel-R; Mel（1a）和Mel（1b））的基因，使得在表征褪黑素的生理作用方面取得了快速进展。在本研究中，部分cDNA编码这四个基因的克隆从鲑鱼（Oncorhynchus凯塔）的眼睛和大脑。基于核苷酸序列，我们开发了这四种mRNA的高灵敏度实时PCR系统。在胚胎和胚胎后阶段（从第-9天到第+180天），在鲑鱼的眼睛和大脑中检查AANAT（1）、AANAT（2）、Mel（1a）和Mel（1b）转录水平的每日节律性的发展。在平行实验中，通过放射免疫测定法测量眼和脑褪黑激素水平。在发育变化和昼夜节律的AANAT mRNA和褪黑激素水平在眼睛和大脑中支持一个假设，即夜间褪黑激素水平的发育增加部分原因是AANAT基因的转录升高。此外，AANAT和Mel-R mRNA在视顶盖、丘脑、下丘脑、小脑和眼睛中的大量表达表明褪黑素可能参与视觉加工和神经内分泌调节，从而参与大麻哈鱼的洄游行为。(C)2004年爱思唯尔公司All rights reserved.
Melatonin and arylalkylamine N-acetyltransferase (AANAT), the rate-limiting enzyme in melatonin synthesis, have taken on special importance in vertebrate circadian biology. Recent identification of genes encoding two AANAT (AANAT(1) and AANAT(2)) and two subtypes of melatonin receptor (Mel-R; Mel(1a) and Mel(1b)) in several fish species has led to rapid advances in characterizing the physiological roles of melatonin. In the present study, partial cDNAs encoding these four genes were cloned from the eye and brain of chum salmon (Oncorhynchus keta). Based on the nucleotide sequences, we developed highly sensitive real-time PCR systems for these four mRNAs. The development of daily rhythmicity in AANAT(1), AANAT(2), Mel(1a), and Mel(1b) transcript levels was examined in the eye and brain of chum salmon during embryonic and post-embryonic stages (from day -9 to day +180). In a parallel experiment, ocular and brain melatonin levels were measured by radioimmunoassay. Parallelism in developmental changes and in circadian rhythms of AANAT mRNAs and melatonin levels in the eye and the brain supports a hypothesis that the developmental increases of nocturnal melatonin levels results partly from the elevated transcription of AANAT genes. Moreover, abundant expression of AANAT and Mel-R mRNAs in the optic tectum, thalamus, hypothalamus, cerebellum, and eye indicates possible roles of melatonin in visual processing and neuroendocrine regulation, through which melatonin might be involved in migratory behavior of chum salmon. (C) 2004 Elsevier Inc. All rights reserved.