Okano T, Fukada Y
Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
Microsc Res Tech. 2001 Apr 1;53(1):72-80. doi: 10.1002/jemt.1070.
Chicken pinealocytes contain three major components of the circadian clock system: 1) a self-sustained oscillator, 2) a photic-input pathway to the oscillator, and 3) an overt output represented by the rhythmic production of melatonin. Even under cultured conditions of isolated pineal gland or dissociated pinealocytes, the input-oscillator-output functions are well maintained. Because of these experimental advantages, chicken pineal gland has been one of the best models for the study of the circadian clock system. Since the finding of a pineal-specific photoreceptive molecule, pinopsin, we have characterized the endogenous phototransduction pathway in the pinealocytes. On the other hand, despite the long history of chick pineal research, the molecular mechanism underlying the pineal clock oscillation has been largely unknown. Our recent characterization of the chick pineal clock genes strongly suggests that they constitute a transcription/translation-based autoregulatory feedback loop, which is very similar to that generating circadian rhythmicity in mammalian SCN.
1）一个自我维持的振荡器；2）一条通向该振荡器的光输入途径；3）以褪黑素的节律性分泌为代表的明显输出。即使在分离的松果体或解离的松果体细胞的培养条件下，输入-振荡器-输出功能也能得到很好的维持。由于这些实验优势，鸡松果体一直是研究生物钟系统的最佳模型之一。自从发现一种松果体特异性光感受分子视锥蛋白以来，我们已经对松果体细胞中的内源性光转导途径进行了表征。另一方面，尽管对鸡松果体的研究历史悠久，但松果体生物钟振荡的分子机制在很大程度上仍然未知。我们最近对鸡松果体生物钟基因的表征强烈表明，它们构成了一个基于转录/翻译的自动调节反馈环，这与在哺乳动物视交叉上核中产生昼夜节律的反馈环非常相似。
