2022 Fiscal Year Final Research Report
Analysis of mechanisms for photoperiod-dependent regulation of reproduction by photoperiodic clock
| Project/Area Number |
20K15842
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 44050:Animal physiological chemistry, physiology and behavioral biology-related
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 光周性 / 概日時計 / 神経分泌細胞 / 電気生理学 / RNA干渉法 / 生殖 |
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| Outline of Final Research Achievements |
Animals sense seasonal changes from photoperiods and appropriately control their reproduction. Some of the circadian clock cells in the brain are thought to function as the photoperiodic clock that measures day length. However, neural mechanisms of photoperiodic reproductive control by the photoperiodic clock were unclear.
In this study, I chose the bean bug Riptortus pedestris as an experimental model to analyze the neural mechanism underlying photoperiodic control. It was found that the expression of clock protein PERIOD in a specific brain region changes according to photoperiodic conditions. Next, I demonstrated that brain glutamate levels photoperiodically change depending on the clock gene period expression. Additionally, I also revealed that glutamate regulates the activity of oviposition-promoting neurons, which contributes to photoperiodic control of oviposition.
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| Free Research Field |
神経生理学
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| Academic Significance and Societal Importance of the Research Achievements |
これまでに、季節に伴う日長変化の読み取りには、体内時計（概日時計）が重要な役割を果たしていることが示唆されていた。しかし、概日時計をもとに日長変化に応じて生殖機能を適切に制御する、脳内神経機構の実体は不明瞭であった。
季節繁殖昆虫を用いた本研究により、概日時計をもとに日長変化に応じて産卵を適切に制御する脳内神経シグナル機構の一端が明らかになった。本研究で日長情報を伝える神経シグナルとして機能することが示唆されたグルタミン酸は、昆虫から哺乳類まで幅広い動物種で脳内情報伝達に使われている。そのため、本研究成果は、動物種全般における概日時計に基づいた生殖の季節性制御機構の解明に繋がることが期待される。
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