Circadian clock system in the pineal gland
Circadian clock system in the pineal gland
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DOI：
10.1385/mn:25:1:019
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发表时间：
2002-02-01
影响因子：
5.1
通讯作者：
Okano, T
中科院分区：
文献类型：
--
作者：
Fukada, Y;Okano, T
松果体是一种神经内分泌器官，在许多非哺乳类脊椎动物中起着中心昼夜振荡器的作用。在许多情况下，松果体保留了光输入和内分泌输出途径，两者每晚都与振荡器相连。这与哺乳动物松果体形成鲜明对比，松果体仅配备有褪黑激素产生的输出，褪黑激素产生受到位于下丘脑视交叉上核（SCN）中的中央昼夜节律振荡器的神经元调节。动物时钟基因的分子研究首先在果蝇中进行，后来在啮齿动物中发展。最近，生物钟基因如Per、Cry、Clock和Bmal在包括鸟类松果体在内的多种脊椎动物的生物钟结构中被发现。鸟类松果体时钟基因表达的时间变化。更类似于哺乳动物SCN中的那些，而不是哺乳动物松果体中的那些。鸟类松果体和哺乳动物SCN似乎共享一个基本的分子框架的时钟振荡器组成的转录/抑制为基础的自动调节反馈回路。昼夜节律的时间保持机制还需要几个翻译后事件，如蛋白质易位和降解过程，其中蛋白质磷酸化对振荡器的稳定24小时循环和/或时钟夹带的光输入途径起着非常重要的作用。
The pineal gland is a neuroendocrine organ that functions as a central circadian oscillator in a variety of nonmammalian vertebrates. In many cases, the pineal gland retains photic input and endocrinal-output pathways both linked nightly to the oscillator. This contrasts well with the mammalian pineal gland equipped only with the output of melatonin production that is subject to neuronal regulation by central circadian oscillator located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Molecular studies on animal clock genes were performed first in Drosophila and later developed in rodents. More recently, clock genes such as Per, Cry, Clock, and Bmal have been found in a variety of vertebrate clock structures including the avian pineal gland. The profiles of the temporal change of the clock gene expression in the avian pineal gland. are more similar to those in the mammalian SCN rather than to those in the mammalian pineal gland. Avian pineal gland and mammalian SCN seem to share a fundamental molecular framework of the clock oscillator composed of a transcription/translation-based autoregulatory feedback loop. The circadian time-keeping mechanism also requires several post-translational events, such as protein translocation and degradation processes, in which protein phosphorylation plays a very important role for the stable 24-h cycling of the oscillator and/or the photic-input pathway for entrainment of the clock.