中文摘要：

昼夜节律现象广泛存在于生物体中，即使简单的原核生物蓝藻，也会表现出昼夜节律行为。生物体昼夜节律受到体内生物钟的调控，目前认为蓝藻生物钟是已知的最简单的生物钟。对蓝藻生物钟分子机制的深入研究，能为人体生物钟及相关疾病的研究提供科学基础。蓝藻生物钟的具体分子机理迄今还有很多未解的问题，但由KaiA／KaiB／KaiC三个蛋白组成的核心振荡器是蓝藻生物钟的关键部分，且能形成不依赖于转录和翻译水平调控的昼夜节律性振荡。文章主要介绍了近几年蓝藻生物钟核心振荡器的研究进展，包括蓝藻生物钟的基本组成、其核心振荡器及Kai～KaiB／KaiC三个蛋白的结构特点和相互作用、核心振荡器的振荡机制，并对其中的关键问题进行了展望。

英文摘要：

Circadian rhythm is a rather generally existing phenomenon in nearly all species on the earth including cyanobacteria. It is widely accepted that circadian rhythm is regulated by circadian clocks, and the circadian clock in cyanobacteria is the simplest one known so far. Although there are many questions remained on the molecular mechanism of the cyanobacterial circadian clock, it is well known that the core oscillator of this circadian clock consists of three proteins （KaiA/KaiB/KaiC）, which can form a circadian oscillator independent of transcriptional/translational regulations. In this paper, the authors reviewed the recent researches on the core oscillator of the cyanobacterial circadian clock, including the composition of the circadian clock, the core-oscillator proteins and their interactions, the molecular mechanism of the oscillator, and the future research perspectives. The better understanding of the cyanobacterial circadian clock will be very meaningful to the study of the circadian clocks and related diseases in human.