PHOTORECEPTORS INVOLVED IN CHLAMYDOMONAS REINHARDTII CIRCADIAN ENTRAINMENT

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 研究中心，而研究中心不一定是研究者所在的机构。 这项研究的长期目标是阐明莱茵衣藻生物钟的生化机制。这种单细胞的真核绿色细胞是动物和植物中许多细胞过程的模型系统。了解它的生物钟将有助于了解生物钟的进化，从而也有助于更好地了解人类的生物钟。实现长期目标的策略是识别负责调节昼夜节律钟以适应每日光/暗周期的光感受器。如果成功的话，光感受器可以被用作一个手柄来研究将信息传递到中央振荡器和可能的振荡器本身的组件的信号转导链。C.莱茵衣藻提供了优于其它模式生物如拟南芥的优势，因为它仅含有有限数量的光感受器。它们分为三类：隐花色素、视紫红质和耳促素。向光蛋白是在高等植物和绿色藻类中发现的蓝光光感受器（Briggs和Christie 2002）。向光素是否参与了生物钟的光照训练尚不完全清楚。另一方面，隐花色素是蓝光光感受器，其被证明参与高等植物和昆虫中的时钟夹带（Cashmore 2003）。它们也存在于哺乳动物中，但作为起搏器的组成部分，在这组生物体中产生昼夜节律振荡。在真菌中，例如粗糙脉孢菌，隐花色素似乎不参与生物钟。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The long-term objectives of the proposed research are to elucidate the biochemical mechanisms underlying the circadian clock in Chlamydomonas reinhardtii. This unicellular, eukaryotic green alga serves as a model system for a number of cell processes in animals and plants. Understanding its circadian clock will contribute to an understanding of circadian clock evolution and thus also help to better understand the circadian clock in humans. The strategy of achieving the long-term objectives is to identify the photoreceptor(s) responsible for adjusting the circadian clock to the daily light/dark cycles. If successful, the photoreceptors can be used as a handle to investigate the signal transduction chain(s) that convey the information to the central oscillator and possibly the components of the oscillator itself. C. reinhardtii provides an advantage over other model organisms such as Arabidopsis thaliana because it contains only a limited number of photoreceptors. They fall into three classes: cryptochromes, rhodopsins, and ototropins. Phototropins are blue-light photoreceptors found in higher plants and green algae (Briggs and Christie 2002). Whether phototropins are involved in lightentrainment of the circadian clock is not completely understood yet. Cryptochromes on the other hand are blue-light photoreceptors that were shown to be involved in clock entrainment in higher plants and insects (Cashmore 2003). They are also found in mammals but serve as components of the pacemaker that creates the circadian oscillation in this group of organisms. In fungi as exemplified by Neurospora crassa, cryptochrome seems not to be involved in the circadian clock.