SATO, Masamitsu



Faculty of Science and Engineering, School of Advanced Science and Engineering

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Concurrent Post 【 display / non-display

  • Affiliated organization   Global Education Center

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

Research Institute 【 display / non-display

  • 2020

    理工学術院総合研究所   兼任研究員

Education 【 display / non-display


    University of Tokyo   Graduate School of Science   Department of Biophysics and Biochemistry  


    University of Tokyo   Graduate School of Science   Department of Biophysics and Biochemistry  


    University of Tokyo   Faculty of Science   Department of Biophysics and Biochemistry  

Degree 【 display / non-display

  • University of Tokyo   Ph.D.

Research Experience 【 display / non-display

  • 2018.04

    Waseda University   Department of Life Science and Medical Bioscience   Professor

  • 2013.04

    Waseda University   Department of Life Science and Medical Bioscience   Associate Professor

  • 2009.09

    ~2012.3: PRESTO researcher, JST

  • 2006.09

    ~2013.3: Assistant Professor, Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo

  • 2006.04

    ~2006.9: JSPS Postdoctoral Fellow for Research Abroad

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Professional Memberships 【 display / non-display


    The Molecular Biology Society of Japan


    Japan Society for Cell Biology


Research Areas 【 display / non-display

  • Genetics

  • Molecular biology

  • Cell biology

Research Interests 【 display / non-display

  • gene expression

  • oocyte

  • Single Cell Analysis

  • cell division

  • mitosis

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Papers 【 display / non-display

  • Mechanisms for Cellular Wake-up in Fission Yeast Revealed by Single-cell RNA-seq

    Hayato Tsuyuzaki, Masahito Hosokawa, Haruko Takeyama, Masamitsu Sato

    Bioscience and Industry (B&I)   78 ( 6 ) 507 - 509  2020.11  [Invited]

    Authorship:Last author, Corresponding author

  • Time-lapse single-cell transcriptomics reveals modulation of histone H3 for dormancy breaking in fission yeast.

    Hayato Tsuyuzaki, Masahito Hosokawa, Koji Arikawa, Takuya Yoda, Naoyuki Okada, Haruko Takeyama, Masamitsu Sato

    Nature communications   11 ( 1 ) 1265 - 1265  2020.03  [Refereed]  [International journal]

    Authorship:Last author, Corresponding author

     View Summary

    How quiescent cells break dormancy is a key issue in eukaryotic cells including cancer. Fungal spores, for example, remain quiescent for long periods until nourished, although the mechanisms by which dormancy is broken remain enigmatic. Transcriptome analysis could provide a clue, but methods to synchronously germinate large numbers of spores are lacking, and thus it remains a challenge to analyse gene expression upon germination. Hence, we develop methods to assemble transcriptomes from individual, asynchronous spore cells of fission yeast undergoing germination to assess transcriptomic changes over time. The virtual time-lapse analyses highlights one of three copies of histone H3 genes whose transcription fluctuates during the initial stage of germination. Disruption of this temporal fluctuation causes defects in spore germination despite no visible defects in other stages of the life cycle. We conclude that modulation of histone H3 expression is a crucial 'wake-up' trigger at dormancy breaking.

    DOI PubMed

  • Module-based construction of plasmids for chromosomal integration of the fission yeast Schizosaccharomyces pombe

    Yasutaka Kakui, Tomonari Sunaga, Kunio Arai, James Dodgson, Liang Ji, Attila Csikasz-Nagy, Rafael Carazo-Salas, Masamitsu Sato

    OPEN BIOLOGY   5 ( 6 )  2015.06  [Refereed]

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    Integration of an external gene into a fission yeast chromosome is useful to investigate the effect of the gene product. An easy way to knock-in a gene construct is use of an integration plasmid, which can be targeted and inserted to a chromosome through homologous recombination. Despite the advantage of integration, construction of integration plasmids is energy-and time-consuming, because there is no systematic library of integration plasmids with various promoters, fluorescent protein tags, terminators and selection markers; therefore, researchers are often forced to make appropriate ones through multiple rounds of cloning procedures. Here, we establish materials and methods to easily construct integration plasmids. We introduce a convenient cloning system based on Golden Gate DNA shuffling, which enables the connection of multiple DNA fragments at once: any kind of promoters and terminators, the gene of interest, in combination with any fluorescent protein tag genes and any selection markers. Each of those DNA fragments, called a 'module', can be tandemly ligated in the order we desire in a single reaction, which yields a circular plasmid in a one-step manner. The resulting plasmids can be integrated through standard methods for transformation. Thus, these materials and methods help easy construction of knock-in strains, and this will further increase the value of fission yeast as a model organism.

    DOI PubMed

  • The Kinetochore Protein Kis1/Eic1/Mis19 Ensures the Integrity of Mitotic Spindles through Maintenance of Kinetochore Factors Mis6/CENP-I and CENP-A

    Hayato Hirai, Kunio Arai, Ryo Kariyazono, Masayuki Yamamoto, Masamitsu Sato

    PLOS ONE   9 ( 11 ) e111905  2014.11  [Refereed]

     View Summary

    Microtubules play multiple roles in a wide range of cellular phenomena, including cell polarity establishment and chromosome segregation. A number of microtubule regulators have been identified, including microtubule-associated proteins and kinases, and knowledge of these factors has contributed to our molecular understanding of microtubule regulation of each relevant cellular process. The known regulators, however, are insufficient to explain how those processes are linked to one another, underscoring the need to identify additional regulators. To find such novel mechanisms and microtubule regulators, we performed a screen that combined genetics and microscopy for fission yeast mutants defective in microtubule organization. We isolated approximately 900 mutants showing defects in either microtubule organization or the nuclear envelope, and these mutants were classified into 12 categories. We particularly focused on one mutant, kis1, which displayed spindle defects in early mitosis. The kis1 mutant frequently failed to assemble a normal bipolar spindle. The responsible gene encoded a kinetochore protein, Mis19 (also known as Eic1), which localized to the interface of kinetochores and spindle poles. We also found that the inner kinetochore proteins Mis6/CENP-I and Cnp1/CENP-A were delocalized from kinetochores in the kis1 cells and that kinetochore-microtubule attachment was defective. Another mutant, mis6, also displayed similar spindle defects. We conclude that Kis1 is required for inner kinetochore organization, through which Kis1 ensures kinetochore-microtubule attachment and spindle integrity. Thus, we propose an unexpected relationship between inner kinetochore organization and spindle integrity.


  • CDK-dependent phosphorylation of Alp7-Alp14 (TACC-TOG) promotes its nuclear accumulation and spindle microtubule assembly

    Naoyuki Okada, Takashi Toda, Masayuki Yamamoto, Masamitsu Sato

    MOLECULAR BIOLOGY OF THE CELL   25 ( 13 ) 1969 - 1982  2014.07  [Refereed]

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    As cells transition from interphase to mitosis, the microtubule cytoskeleton is reorganized to form the mitotic spindle. In the closed mitosis of fission yeast, a microtubule-associated protein complex, Alp7-Alp14 (transforming acidic coiled-coil-tumor overexpressed gene), enters the nucleus upon mitotic entry and promotes spindle formation. However, how the complex is controlled to accumulate in the nucleus only during mitosis remains elusive. Here we demonstrate that Alp7-Alp14 is excluded from the nucleus during interphase using the nuclear export signal in Alp14 but is accumulated in the nucleus during mitosis through phosphorylation of Alp7 by the cyclin-dependent kinase (CDK). Five phosphorylation sites reside around the nuclear localization signal of Alp7, and the phosphodeficient alp7-5A mutant fails to accumulate in the nucleus during mitosis and exhibits partial spindle defects. Thus our results reveal one way that CDK regulates spindle assembly at mitotic entry: CDK phosphorylates the Alp7-Alp14 complex to localize it to the nucleus.


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Misc 【 display / non-display

  • Systems level understanding of cell polarity regulation

    Attila Csikasz-Nagy, Federico Vaggi, James Dodgson, Anatole Chessel, Marco Geymonat, Marco Giordan, Kunio Arai, Masamitsu Sato, Rafael Edgardo Carazo Salas

    YEAST   32   S247 - S247  2015.09

    Research paper, summary (international conference)  

Awards 【 display / non-display

  • Waseda University Research Award


    Winner: SATO, Masamitsu

  • Waseda University Teaching Award, The President Award

    2018   Waseda University  

  • Waseda University Teaching Award


    Winner: SATO, Masamitsu

  • The Young Scientists’ Prize, The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology


  • Human Frontier Science Program (HFSP) Young Investigator Grant


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Research Projects 【 display / non-display

  • Regulatory mechanisms of meiosis

  • Cell cycle regulation specific to the interkinesis period between Meiosis I and Meiosis II

  • Analysis of novel functions of microtubules that bridge meiotic recombination and chromosome segregation

  • Regulatory Mechanisms of Meiosis in Fission Yeast

  • 減数分裂における細胞分裂装置の再編成機構


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Specific Research 【 display / non-display

  • 微小管の時空間的制御のメカニクス異常が原因で起きる疾患を組織レベルで追究する


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  • シングルセル・オミクス解析による、細胞が休眠から目覚める分子機構の解明


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  • クロマチン動態解析のためのシングルセル・オミクス基盤技術の整備


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  • 高齢卵子における微小管異常と不妊との関連


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  • 構造クラスタ分類によるncRNA新機能の発見


     View Summary

    分裂酵母S. pombeにおいては,およそ1,800種類の非コードRNAが存在することが知られている。これらには細胞内でなんらかの機能を発揮するものがあると考えられるが,これまでのところ機能が解明されているものはごく一部のみであり,大部分は機能未定の状態である。そこで本研究では,これらの非コードRNAのなかから細胞内で何らかの機能を発揮するものを探索することを主目的としてスクリーンをおこなっている。

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Syllabus 【 display / non-display

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