Kanai, Akio



Faculty of Environment and Information Studies (Shonan Fujisawa)



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  • Dr. Akio Kanai was born in Tokyo, Japan. He graduated from Waseda University in 1985, and obtained his PhD in molecular biology at the University of Tokyo in 1990. He finished postdoctoral training at the National Institutes of Health, USA (1990-1992), and he was appointed a researcher in the Tokyo Metropolitan Institute of Medical Science (1992-1996). He was a group leader for the Japan Science and Technology Corporation (JST), ERATO Project Group (1996-2001). He was an Associate Professor at the Institute for Advanced Biosciences, Keio University (2001-2006) and accepted a full professorship in April, 2006. His major research fields include molecular cellular biology and gene regulation in a variety of organisms. His work in life sciences has led him to his present research into RNA-binding proteins and non-coding RNAs.

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  • 学部や大学院学生の教育について

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  • 遺伝情報の流れとしてDNA→RNA→蛋白質(セントラルドグマ)が提唱されたのは60年も前のことです。この考え方は基本軸として揺るがないでしょうが、1970-80年代における、逆転写酵素や酵素活性を有したRNA (リボザイム)の発見等で、その修正を要求されてきました。また、21世紀になってから極めて沢山のNon-coding RNAが発見されたことで、セントラルドグマにおけるRNA分子そのものの働きが無視できない状況になってきました。本プロジェクトでは、遺伝子制御に関わる機能性RNAやRNA結合蛋白質およびRNA関連酵素に焦点をあて、RNAレベルで制御される新しいメカニズムの解明を目的とします。またこの研究を通して、遺伝情報制御および成立過程に関わる分子進化的な考察を行います。さらに、これらの知見を基盤として、生命の起源、進化、遺伝子制御について考察していきます。

Career 【 Display / hide

  • 1990.10

    米国国立衛生研究所(NIH) ,博士訪問研究員

  • 1992.11

    (財)東京都臨床医学総合研究所 ,研究員

  • 1996.04


  • 2001.04


  • 2006.04


Academic Background 【 Display / hide

  • 1985.03

    Waseda University, Faculty of Education

    University, Graduated

  • 1987.03

    Waseda University, Graduate School, Division of Science and Engineeri

    Graduate School, Completed, Master's course

  • 1990.03

    The University of Tokyo, Graduate School, Division of Pharmaceutical Scienc, 生命薬学専攻

    Graduate School, Completed, Doctoral course

Academic Degrees 【 Display / hide

  • 薬学 , The University of Tokyo, 1990.03


Research Areas 【 Display / hide

  • Genome biology

  • Molecular biology (Molecular Biology)

  • Evolutionary biology

Research Keywords 【 Display / hide

  • Non-codingRNA, transfer RNA, Archaea, RNA-related enzymes, Genetic code

Research Themes 【 Display / hide

  • (1) RNA-binding proteins & RNA-related enzymes (2) Non-coding RNAs (3) microRNAs (4) Sense-antisense gene regulation (5) DNA replication (primer RNA processing) (6) Post-transcriptional RNA proce, 



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  • Proteomic and metabolomic analyses uncover sex-specific regulatory pathways in mouse fetal germline differentiation

    Hayashi, Y., Mori, M., Igarashi, K., Tanaka, K., Takehara, A., Ito-Matsuoka, Y., Kanai, A., Yaegasgi, N., Soga, T. and Matsui, Y.

    Biology of Reproduction (Oxford University Press)  103 ( 4 ) 717 - 735 2020.07

    Research paper (scientific journal), Accepted,  ISSN  00063363

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    Regulatory mechanisms of germline differentiation have generally been explained via the function of signaling pathways, transcription factors, and epigenetic regulation; however, little is known regarding proteomic and metabolomic regulation and their contribution to germ cell development. Here, we conducted integrated proteomic and metabolomic analyses of fetal germ cells in mice on embryonic day (E)13.5 and E18.5 and demonstrate sex- and developmental stage-dependent changes in these processes. In male germ cells, RNA processing, translation, oxidative phosphorylation, and nucleotide synthesis are dominant in E13.5 and then decline until E18.5, which corresponds to the prolonged cell division and more enhanced hyper-transcription/translation in male primordial germ cells and their subsequent repression. Tricarboxylic acid cycle and one-carbon pathway are consistently upregulated in fetal male germ cells, suggesting their involvement in epigenetic changes preceding in males. Increased protein stability and oxidative phosphorylation during female germ cell differentiation suggests an upregulation of aerobic energy metabolism, which likely contributes to the proteostasis required for oocyte maturation in subsequent stages. The features elucidated in this study shed light on the unrevealed mechanisms of germ cell development.

  • Behavioral and brain- transcriptomic synchronization between the two opponents of a fighting pair of the fish Betta splendens.

    Vu, T.-D., Iwasaki, Y., Shigenobu, S., Maruko, A., Oshima, K., Iioka E., Huang, C.-L., Abe, T., Tamaki, S., Lin, Y.-W., Chen, C.-K., Lu, M.-Y., Hojo, M., Wang, H.-V., Tzeng, S.-F., Huang, H.-J., Kanai, A., Gojobori, T., Chiang, T.-Y., Sun, H. S., Li, W.-H., and Okada, N.

    PLOS Genetics (PLOS)  16 ( 6 )  2020.06

    Research paper (scientific journal), Accepted,  ISSN  15537390

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    Conspecific male animals fight for resources such as food and mating opportunities but typically stop fighting after assessing their relative fighting abilities to avoid serious injuries. Physiologically, how the fighting behavior is controlled remains unknown. Using the fighting fish Betta splendens, we studied behavioral and brain-transcriptomic changes during the fight between the two opponents. At the behavioral level, surface-breathing, and biting/striking occurred only during intervals between mouth-locking. Eventually, the behaviors of the two opponents became synchronized, with each pair showing a unique behavioral pattern. At the physiological level, we examined the expression patterns of 23,306 brain transcripts using RNA-sequencing data from brains of fighting pairs after a 20-min (D20) and a 60-min (D60) fight. The two opponents in each D60 fighting pair showed a strong gene expression correlation, whereas those in D20 fighting pairs showed a weak correlation. Moreover, each fighting pair in the D60 group showed pair-specific gene expression patterns in a grade of membership analysis (GoM) and were grouped as a pair in the heatmap clustering. The observed pair-specific individualization in brain-transcriptomic synchronization (PIBS) suggested that this synchronization provides a physiological basis for the behavioral synchronization. An analysis using the synchronized genes in fighting pairs of the D60 group found genes enriched for ion transport, synaptic function, and learning and memory. Brain-transcriptomic synchronization could be a general phenomenon and may provide a new cornerstone with which to investigate coordinating and sustaining social interactions between two interacting partners of vertebrates.

  • Editorial: Current Advances in the Research of RNA Regulatory Enzymes

    Kanai, A. and Yoshihisa, T.

    Frontiers in Genetics (Frontiers)  10 ( 973 )  2019.10

    Research paper (scientific journal), Joint Work, Accepted

  • Large-scale Molecular Evolutionary Analysis Uncovers a Variety of Polynucleotide Kinase Clp1 Family Proteins in the Three Domains of Life

    Saito, M., Sato, A., Nagata, S., Tamaki, S., Tomita, M., Suzuki, H., and Kanai, A.

    Genome Biology and Evolution (Genome Biology and Evolution)  11 ( 10 ) 2713 - 2726 2019.09

    Research paper (scientific journal), Accepted

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    © 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. Clp1, a polyribonucleotide 5′-hydroxyl kinase in eukaryotes, is involved in pretRNA splicing and mRNA 3′-end formation. Enzymes similar in amino acid sequence to Clp1, Nol9, and Grc3, are present in some eukaryotes and are involved in prerRNA processing. However, our knowledge of how these Clp1 family proteins evolved and diversified is limited. We conducted a large-scale molecular evolutionary analysis of the Clp1 family proteins in all living organisms for which protein sequences are available in public databases. The phylogenetic distribution and frequencies of the Clp1 family proteins were investigated in complete genomes of Bacteria, Archaea and Eukarya. In total, 3,557 Clp1 family proteins were detected in the three domains of life, Bacteria, Archaea, and Eukarya. Many were from Archaea and Eukarya, but a few were found in restricted, phylogenetically diverse bacterial species. The domain structures of the Clp1 family proteins also differed among the three domains of life. Although the proteins were, on average, 555 amino acids long (range, 196-2,728), 122 large proteins with >1,000 amino acids were detected in eukaryotes. These novel proteins contain the conserved Clp1 polynucleotide kinase domain and various other functional domains. Of these proteins, >80% were from Fungi or Protostomia. The polyribonucleotide kinase activity of Thermus scotoductus Clp1 (Ts-Clp1) was characterized experimentally. Ts-Clp1 preferentially phosphorylates single-stranded RNA oligonucleotides (Km value for ATP, 2.5 μM), or single-stranded DNA at higher enzyme concentrations. We propose a comprehensive assessment of the diversification of the Clp1 family proteins and the molecular evolution of their functional domains.

  • Systematic analysis of the binding surfaces between tRNAs and their respective aminoacyl tRNA synthetase based on structural and evolutionary data

    Tamaki, S., Tomita, M., Suzuki, H. and Kanai, A.

    Frontiers in Genetics (Frontiers in Genetics)  8 ( 227 )  2018.01

    Research paper (scientific journal), Accepted

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    © 2018 Tamaki, Tomita, Suzuki and Kanai. To determine the mechanism underlying the flow of genetic information, it is important to understand the relationship between a tRNA and its binding enzyme, a member of the aminoacyl-tRNA synthetase (aaRS) family. We have developed a novel method to project the interacting regions of tRNA-aaRS complexes, obtained from their three-dimensional structures, onto two-dimensional space. The interacting surface between each tRNA and its aaRS was successfully identified by determining these interactions with an atomic distance threshold of 3.3 Å. We analyzed their interactions, using 60 mainly bacterial and eukaryotic tRNA-aaRS complexes, and showed that the tRNA sequence regions that interacted most strongly with each aaRS are the anticodon loop and the CCA terminal region, followed by the D-stem. A sequence conservation analysis of the canonical tRNAs was conducted in 83 bacterial, 182 archaeal, and 150 eukaryotic species. Our results show that the three tRNA regions that interact with the aaRS and two additional loop regions (D-loop and TψC-loop) known to be important for formation of the tRNA L-shaped structure are broadly conserved. We also found sequence conservations near the tRNA discriminator in the Bacteria and Archaea, and an enormous number of noncanonical tRNAs in the Eukaryotes. This is the first global view of tRNA evolution based on its structure and an unprecedented number of sequence data.

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  • 微生物生態系による原子炉内物体の腐食・変質に関する評価研究


    文部科学省, 英知を結集した原子力科学技術・人材育成事業 国際協力型廃炉研究プログラム(廃炉加速化研究プログラム), 金井昭夫, Elena Shagimardanova, Research grant, Principal Investigator

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  • 多様性を有するRNAキナーゼの進化情報解析とその情報に基づいた酵素機能の改変


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 金井 昭夫, Grant-in-Aid for Scientific Research (C), Principal Investigator

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  • 「平成29年度『科研費』審査委員」表彰

    金井昭夫, 2017.09, 独立行政法人 日本学術振興会

    Country: 日本

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Courses Previously Taught 【 Display / hide


    Keio University, 2018, Autumn Semester, Major subject


    Keio University, 2018, Autumn Semester


    Keio University, 2018, Autumn Semester, Major subject


    Keio University, 2018, Spring Semester, Major subject


    Keio University, 2018, Spring Semester, Major subject, Lecture

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Memberships in Academic Societies 【 Display / hide

  • RNA Society

  • American Association for the Advancement of Science (AAAS)

  • American Society for Microbiology (ASM)

  • 日本分子生物学会

  • 日本生化学会


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