| Project/Area Number |
17K19247
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Agricultural chemistry and related fields
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| Research Institution | Ritsumeikan University |
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Principal Investigator |
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| Project Period (FY) |
2017-06-30 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
Fiscal Year 2018: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2017: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
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| Keywords | 体内時計 / シアノバクテリア / 概日時計 / シアノバテクリア / 共生 / 生物時計 |
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| Outline of Final Research Achievements |
Life on Earth is equipped with circadian clock, which allows it to adapt its life cycle to the 24-hour day and night environment. The circadian clocks of mammals, higher plants, insects, fungi, and prokaryotes are being analyzed at the molecular level. It is known that clock proteins have been created through a unique evolutionary process from different evolutionary origins. The diversity of circadian clock is very interesting for the evolution of organisms.
Cyanobacteria, the simplest organisms with circadian clock, have a kaiABC gene as the core of their circadian clock. The three Kai proteins that form the circadian clock are encoded by kaiABC genes. In this study, we analyzed Kai proteins, which can be considered the most primitive circadian clock, and transfer them to other organisms. The diversity and evolution of Kai proteins were discussed by trying them out.
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| Academic Significance and Societal Importance of the Research Achievements |
生物界全体におけるKaiタンパク質の分布は、シアノバクテリアと一部の細菌に限られ、植物は異なる時計システムを有する。植物の葉緑体の起源は、シアノバクテリアの祖先生物の細胞内共生によると提唱されているが、内部共生過程においてKai時計システムが欠落したことを示唆している。本研究により、Kaiタンパク質は異生物内においても機能的に働くことが明らかになった。つまり、何らかのホスト生物自身が有する固有のシステムと、Kai時計システムが和合できない理由があると考えられた。また、時計タンパク質のホモログは、時計としての機能はもたず、時計機能を補助する役割をもち、進化の過程で多様性が生じたことが示唆された。
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