松果体昼夜节律生物钟分子机制的研究进展

在各种非哺乳类脊椎动物中 ,松果体起着中枢昼夜节律振荡器的作用。近来 ,在鸟类松果体中相继发现了几种钟基因 ,如Per、Cry、Clock和Bmal等 ,其表达的时间变化规律与哺乳类视交叉上核 (SCN)的非常相似。钟的振荡由其自身调控反馈环路的转录和翻译组成 ,鸟类松果体和哺乳类SCN似乎具有共同的钟振荡基本分子构架 ;若干钟基因产物作为正向或负向调节子影响钟的振荡 ;昼夜性的控时机制同时也需要翻译后事件的参与。这些过程对钟振荡器的稳定性和 /或钟导引的光输入通路有着重要的调控作用

Advances in study on molecular mechanism of circadian clock in pineal gland

The pineal gland functions as a central circadian oscillator in a variety of nonmammalian vertebrates. 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 suprachiasmatic nucleus (SCN) of the hypothalamus. 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. Some products of the clock genes serve as positive or negative regulators influencing the clock oscillation. The circadian time-keeping mechanism is also involved in several post-translational events. The above-mentioned processes play a quite important role in the stability of the oscillator and / or the photic-input pathway for entrainment of the clock.