Biosynthesis and function of a novel tRNA modification ectopically acquired by a disease associated mutation

• Project/Area Number: 20K21243
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 37:Biomolecular chemistry and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Suzuki Takeo 東京大学, 大学院工学系研究科(工学部), 講師 (90533125)
• Project Period (FY): 2020-07-30 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000); Fiscal Year 2021: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2020: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
• Keywords: tRNA / ミトコンドリア / 点変異 / 遺伝暗号解読 / 疾患

Outline of Research at the Start

ミトコンドリア内部で転写される転移RNA(tRNA)への転写後修飾は、tRNAが機能を持つために重要な過程であるため、修飾の欠損は一般に疾患の要因となる。今回、tRNAへの疾患関連点変異により、点変異部位とは異なる、本来正常な配列と言える部位に新規修飾が獲得されることを見出した。この新規修飾について生合成機構や特に遺伝暗号解読における役割の解明を目指す。得られる研究成果は、既往の修飾「欠損」疾患とは全く逆の、修飾「獲得」疾患の初めての例証になる可能性があるだけでなく、疾患のメカニズムの一端が明らかになることで、疾患の予防や克服に向けた応用へとつながることも期待している。

Outline of Final Research Achievements

Structural analyses enabled us to predict a chemical structure of the novel modification found in human mitochondrial tRNA-Met with a pathogenic point mutation. We also predict a modifying enzyme based on the structure and demonstrated that the enzyme can reconstitute the modification in cells by over expression and in vitro by using recombinant protein. To perform ribosome binding assay for measurement of the modification’s decoding ability, we optimized the reaction condition of the assay by using anticodon stem-loop (ASL) as a model tRNA substrate. Although the binding efficiency still did not increase much, the assay condition was finally determined.

Academic Significance and Societal Importance of the Research Achievements

疾患点変異に伴い変異部位と異なる位置に新たに獲得されたRNA修飾は、新規な化学構造を持っていた。このことはヒトにおけるRNA修飾の構造や機能の多様性を表していると言える。当該修飾は疾患を亢進する役割を持つと考えらえることから、今回特定された生合成経路を阻害することが、点変異に起因する疾患の治療や予防につながるといった応用が機体される。

Research Products

• [Journal Article] Mass spectrometric analysis of mRNA 5′ terminal modifications (2021)
  • Author(s): Akichika, S., Suzuki, T., Suzuki, T.
  • Journal Title: Methods Enzymol Volume: 658 Pages: 407-418
  • DOI: 10.1016/bs.mie.2021.06.012
  • ISBN: 9780128235850
  • Peer Reviewed
• [Journal Article] RNA修飾と疾患 (2021)
  • Author(s): 鈴木 健夫、鈴木 勉
  • Journal Title: 月刊「細胞」 Volume: 53 Pages: 880-883
• [Journal Article] N6-methyladenosine (m6A) is an endogenous A3 adenosine receptor ligand (2021)
  • Author(s): Ogawa Akiko、Nagiri Chisae、Shihoya Wataru、Inoue Asuka、Kawakami Kouki、Hiratsuka Suzune、Aoki Junken、Ito Yasuhiro、Suzuki Takeo、Suzuki Tsutomu、Inoue Toshihiro、Nureki Osamu、Tanihara Hidenobu、Tomizawa Kazuhito、Wei Fan-Yan
  • Journal Title: Molecular Cell Volume: 81 Issue: 4 Pages: 674-674
  • DOI: 10.1016/j.molcel.2020.12.038
  • Peer Reviewed
• [Journal Article] Loss of Ftsj1 perturbs codon-specific translation efficiency in the brain and is associated with X-linked intellectual disability (2021)
  • Author(s): Nagayoshi Y.、Chujo T.、Hirata S.、Nakatsuka H.、Chen C.-W.、Takakura M.、Miyauchi K.、Ikeuchi Y.、Carlyle B. C.、Kitchen R. R.、Suzuki T.、Katsuoka F.、Yamamoto M.、Goto Y.、Tanaka M.、Natsume K.、Nairn A. C.、Suzuki T.、Tomizawa K.、Wei F.-Y.
  • Journal Title: Science Advances Volume: 7 Issue: 13
  • DOI: 10.1126/sciadv.abf3072
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Complete chemical structures of human mitochondrial tRNAs (2020)
  • Author(s): Suzuki Takeo、Yashiro Yuka、Kikuchi Ittoku、Ishigami Yuma、Saito Hironori、Matsuzawa Ikuya、Okada Shunpei、Mito Mari、Iwasaki Shintaro、Ma Ding、Zhao Xuewei、Asano Kana、Lin Huan、Kirino Yohei、Sakaguchi Yuriko、Suzuki Tsutomu
  • Journal Title: Nature Communications Volume: 11 Issue: 1 Pages: 1-15
  • DOI: 10.1038/s41467-020-18068-6
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Mass Spectrometric Analysis of Mitochondrial RNA Modifications (2020)
  • Author(s): Ishigami Yuma、Suzuki Tsutomu、Suzuki Takeo
  • Journal Title: Methods in Molecular Biology Volume: 2192 Pages: 89-101
  • DOI: 10.1007/978-1-0716-0834-0_8
  • ISBN: 9781071608333, 9781071608340
  • Peer Reviewed
• [Journal Article] ミトコンドリアtRNA修飾とミトコンドリア病 (2020)
  • Author(s): 鈴木健夫
  • Journal Title: 遺伝子医学MOOK 35号 ミトコンドリアと病気 Volume: 35 Pages: 268-274
• [Presentation] Restoration of mitochondrial function through activation of hypomodified tRNAs with pathogenic mutations associated with mitochondrial diseases (2021)
  • Author(s): Tomoda, E., Nagao, A., Shirai, Y., Suzuki, T., Brendan, B., Suzuki, T.
  • Organizer: 44th Annual meeting of the MBSJ
• [Presentation] Identification and characterization of novel tRNA methyltransferases in higher eukaryotes (2021)
  • Author(s): Mineo, A., Akichika, S., Sakaguchi, Y., Shichino, Y., Mito, M., Iwasaki, S., Suzuki, T., Suzuki, T.
  • Organizer: 44th Annual meeting of the MBSJ
• [Remarks] ヒトミトコンドリアtRNA修飾の全体像を解明―RNA修飾異常疾患の究明へ大きな前進
  • URL: https://www.t.u-tokyo.ac.jp/foe/press/setnws_202008311155455788959888.html