Nakajima Masato, Imai Keiko, Ito Hiroshi, Nishiwaki Taeko, Murayama Yoriko, Iwasaki Hideo, Oyama Tokitaka, Kondo Takao
Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
Science. 2005 Apr 15;308(5720):414-5. doi: 10.1126/science.1108451.
Kai proteins globally regulate circadian gene expression of cyanobacteria. The KaiC phosphorylation cycle, which persists even without transcription or translation, is assumed to be a basic timing process of the circadian clock. We have reconstituted the self-sustainable oscillation of KaiC phosphorylation in vitro by incubating KaiC with KaiA, KaiB, and adenosine triphosphate. The period of the in vitro oscillation was stable despite temperature change (temperature compensation), and the circadian periods observed in vivo in KaiC mutant strains were consistent with those measured in vitro. The enigma of the circadian clock can now be studied in vitro by examining the interactions between three Kai proteins.
Kai蛋白全局调控蓝细菌的昼夜节律基因表达。即使在没有转录或翻译的情况下仍持续存在的KaiC磷酸化循环，被认为是生物钟的基本计时过程。我们通过将KaiC与KaiA、KaiB和三磷酸腺苷一起孵育，在体外重建了KaiC磷酸化的自我持续振荡。尽管温度变化（温度补偿），体外振荡的周期仍保持稳定，并且在KaiC突变株体内观察到的昼夜节律周期与体外测量的周期一致。现在可以通过研究三种Kai蛋白之间的相互作用在体外研究生物钟的奥秘。
