Mittag Maria, Wagner Volker
Institut für Allgemeine Botanik, Friedrich-Schiller-Universität Jena, Am Planetarium 1, D-07743 Jena, Germany.
Biol Chem. 2003 May;384(5):689-95. doi: 10.1515/BC.2003.077.
The green unicellular alga Chlamydomonas reinhardtii, also called 'green yeast', emerged in the past years as a model organism for specific scientific questions such as chloroplast biogenesis and function, the composition of the flagella including its basal apparatus, or the mechanism of the circadian clock. Sequencing of its chloroplast and mitochondrial genomes have already been completed and a first draft of its nuclear genome has also been released recently. In C. reinhardtii several circadian rhythms are physiologically well characterized, and one of them has even been shown to operate in outer space. Circadian expression patterns of nuclear and plastid genes have been studied. The mode of regulation of these genes occurs at the transcriptional level, although there is also evidence for posttranscriptional control. A clock-controlled, phylogenetically conserved RNA-binding protein was characterized in this alga, which interacts with several mRNAs that all contain a common cis-acting motif. Its function within the circadian system is currently under investigation. This review summarizes the current state of the knowledge about the circadian system in C. reinhardtii and points out its potential for future studies.
绿色单细胞藻类莱茵衣藻，也被称为“绿色酵母”，在过去几年中成为研究特定科学问题的模式生物，这些问题包括叶绿体的生物发生与功能、鞭毛（包括其基部结构）的组成，或昼夜节律钟的机制。其叶绿体和线粒体基因组的测序已经完成，并且其核基因组的初稿最近也已发布。在莱茵衣藻中，几种昼夜节律在生理上已得到充分表征，其中一种甚至已被证明能在外太空发挥作用。人们已经研究了核基因和质体基因的昼夜表达模式。这些基因的调控方式发生在转录水平，不过也有证据表明存在转录后控制。在这种藻类中鉴定出一种受生物钟控制、系统发育保守的RNA结合蛋白，它与几种均含有一个共同顺式作用基序的mRNA相互作用。目前正在研究其在昼夜节律系统中的功能。这篇综述总结了关于莱茵衣藻昼夜节律系统的当前知识状态，并指出了其未来研究的潜力。
