| Project/Area Number |
18K14621
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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 43010:Molecular biology-related
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Murakami Ryo 東京大学, 大学院理学系研究科(理学部), 助教 (00783870)
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| Project Period (FY) |
2018-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2019: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | piRNA / RNAサイレンシング / RNAヘリカーゼ / Argonaute / 生殖細胞 / トランスポゾン / ピンポンサイクル |
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| Outline of Final Research Achievements |
Siwi- and Ago3-piRNA induced silencing complex (piRISC) in silkworm germ cells cooperate the ping-pong cycle to produce Ago3- and Siwi-piRISC, respectively, by cleaving transposon transcripts, leading to transposon repression. In this study, we show that DEAD-box polypeptide 43 (DDX43) binds Ago3-piRISC and liberate RNAs from the complex to facilitate Siwi-piRISC production in the ping-pong cycle. Biochemical analysis using a series of DDX43 mutants revealed individual and collaborative functions of the two domains: The helicase core is responsible for Ago3 binding and ATP hydrolysis while the KH domain greatly enhances the ATPase activity owned by the helicase core. The full exertion of RNA-binding activity of DDX43 requires both KH domain and the helicase core. This study revealed the molecular function of DDX43 in germ-specific piRISC biogenesis and gained new insights into the roles of KH domain and the helicase core.
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| Academic Significance and Societal Importance of the Research Achievements |
piRNAは生殖細胞特異的な小分子RNAであり、にトランスポゾンを抑制することでゲノム情報の安定化に寄与している。piRNAの増幅とトランスポゾンの抑制を同時に行うピンポンサイクル経路は生物間で保存されており、この経路の理解はpiRNAの機能解明に重要である。本研究で同定したDDX43は、ピンポンサイクル経路の駆動に必要なRNAヘリカーゼであり、その機能解明は生殖細胞の発生機構の一端を明らかにするものである。
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