Temporal integration of cellular system by circadian clock in cyanobacteria

蓝藻生物钟对细胞系统的时间整合

基本信息

批准号：
15GS0308
负责人：
KONDO Takao
金额：
$ 264.33万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Creative Scientific Research
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2007
项目状态：
已结题

项目摘要

In the cyanobacterium, Synechococcus elongatus PCC 7942, three genes (kaiA, kaiB and kaiC) code essential components of the circadian clock, and negative feedback regulation of kaiBC expression by Kai proteins was confirmed and proposed as a core loop of prokaryotic circadian oscillator. However, it would be difficult to explain the key feature of circadian oscillation, that is, about 24-hour periodicity and its stability, by the feedback model of clock gene expression. To address this question, we developed DNA-chips and bioluminescence reporter strain for all transcripts and elucidated basic feature of global regulation of transcription by Kai proteins.Recently, by studying kaiC phosphorylation in continuous darkm conditions, we found robust circadian cycling of kaiC phosphorylation even without kaiBC mRNA accumulation. Moreover, by incubating kaiC with kaiA, kaiB, and ATP, we found the self-sustainable circadian oscillation of kaiC phosphorylation. The in vitro oscillation of kaiC phosphorylation persisted for at least three cycles and the period was compensated against temperature change. These results demonstrate that the oscillation of kaiC phosphorylation is the primary pacemaker of the cyanobacterial circadian clock. We further analyzed the in vitro kaiC phosphorylation cycle and found that extraordinarily weak (16 ATP/day/kaiC) but temperature-compensated ATPase activity of kaiC is a key reaction in defining the circadian period.

在蓝细菌中，元技术弹药PCC 7942，三个基因（KAIA，KAIB和KAIB）代码代码的昼夜节律时钟的基本要素，以及KAI蛋白对KAIBC表达的负面反馈得到证实，并被证实，并建议用作Prokaryotic Cirkaryotic Ciffadian示波器的核心循环。但是，很难通过时钟基因表达的反馈模型来解释昼夜节律振荡的关键特征，即大约24小时的周期性及其稳定性。为了解决这个问题，我们为所有转录本开发了DNA-CHIPS和生物发光报告菌株，并阐明了KAI蛋白对全球转录的基本调节的基本特征。绝对地研究了连续的Darkm条件下的KAIC磷酸化，我们发现了Kaic phosclation conteclian cycliant of Kaic phlosclation，即使没有Kaic phossib phossclation rna praphostian cyclation。此外，通过与Kaia，Kaib和ATP一起孵育KAIC，我们发现了KAIC磷酸化的昼夜节律振荡。 KAIC磷酸化的体外振荡至少持续了三个循环，并且对温度变化进行了补偿。这些结果表明，KAIC磷酸化的振荡是蓝细菌昼夜节律时钟的主要起搏器。我们进一步分析了体外KAIC磷酸化周期，并发现非常弱（16 atp/day/kaic），但是KAIC温度补偿的ATPase活性是定义昼夜节律时期的关键反应。

项目成果

期刊论文数量（114）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Role of KaiC phosphorylation in the circadian clock system of Synechococcus elongatus PCC 7942

DOI：
10.1073/pnas.0403906101
发表时间：
2004-09-21
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
影响因子：
11.1
作者：
Nishiwaki, T;Satomi, Y;Kondo, T
通讯作者：
Kondo, T

A novel mutation in kaiC affects resetting of the cyanobacterial circadian clock