生物钟翻译后核心振荡机制

The research progresses in post-translational oscillation of circadian clock systems

生物钟现象是普遍存在于生物体内的一种周期约24小时的节律性振荡现象。就生物钟的振荡机制而言,依赖于转录-翻译的负反馈回路(transcriptional/translational feedback loop,TTFL)机制,这也是最经典的振荡机制。但是近些年来,众多新的研究发现,生物钟翻译后振荡(post-translational oscillation,PTO)机制也具有重要作用,并在古生菌、原核生物和真核生物中都有发现。目前研究最深入的生物钟PTO是原核生物蓝藻中由Kai A/Kai B/Kai C三个蛋白构成的生物钟振荡。近几年来,一类普遍存在于几乎所有生物体内的过氧化物氧还蛋白(peroxiredoxin,PRX)依赖的生物钟振荡,也取得了一系列的重要研究进展。本文对近些年来生物钟PTO的研究进行了综述,并介绍了PTO与TTFL两种生物钟机制的相互联系。

Circadian clocks are rhythmic oscillations with the period of about 24 hours that generally exist in biological organisms. In circadian clocks, the transcriptional/translational feedback loop（TTFL） model is considered as the most common mechanism. However, in recent years, many new studies have found that post-translational oscillation（PTO） mechanism also plays an important role. Independent of the transcriptional/translational regulations, PTO has been revealed to exist in archaea, prokaryotes and eukaryotes. The best studied PTO system of the circadian clock is the circadian system of cyanobacteria, driven by three proteins, KaiA, KaiB, and KaiC. Very recently, the thioredoxin peroxidase（PRX） system has been found to be another important PTO regulatory system, widely existing in most organisms. In this paper, we have reviewed the recent studies on the PTO systems of circadian clocks, and discussed the mechanisms of coupling PTO to TTFL.