Yagisawa Fumi

写真a

Title

Associate Professor

Researcher Number(JSPS Kakenhi)

70757658
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Current Affiliation Organization 【 display / non-display 】

  • Concurrently   University of the Ryukyus   Graduate School of Engineering and Science   Chemistry, Biology and Marine Science   Associate Professor  

  • Duty   University of the Ryukyus   Research Facility Center   Associate Professor  

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External Career 【 display / non-display 】

  • 2015.04
    　
    　

    University of the Ryukyus, Instrumental Research Center, Associate Professor  

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Research Areas 【 display / non-display 】

  • Life Science / Cell biology

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Published Papers 【 display / non-display 】

  • Costs of photosynthesis and cellular remodeling in trophic transitions of the unicellular red alga Galdieria partita.

    Yamashita S, Hirooka S, Fujiwara T, Zhou B, Yagisawa F, Tamashiro K, Murakami H, Awai K, Miyagishima SY

    Communications biology   8 ( 1 ) 891   2025.06 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

  • Heterotrophic unicellular eukaryotes feeding on the unicellular red alga Cyanidiococcus sp. in moderately hot geothermal sulfuric springs.

    Sunada Y, Tsujino D, Yamashita S, Hsieh WH, Tamashiro K, Izumi J, Yagisawa F, Zhou B, Hirooka S, Fujiwara T, Miyagishima SY

    FEMS microbiology ecology   101 ( 5 )   2025.04 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    Sulfuric acidic hot springs (<pH 4.0, >37°C) are found in volcanic regions worldwide, where various bacteria, archaea, and the unicellular red algae Cyanidiophyceae dominate. Regarding heterotrophic eukaryotes, the only known species was the thermophilic amoeboflagellate Tetramitus thermacidophilus (class Eutetramitea, phylum Heterolobosea), which feeds on surrounding bacteria and archaea. In this study, we investigated three sulfuric hot springs (34.7°C-50°C, ∼pH 2.0) in Japan to determine whether other heterotrophic eukaryotes inhabit these environments. As a result, we isolated and identified cultures of four species capable of surviving at pH 2.0 and 40°C: Allovahlkampfia sp. (Eutetramitea, Heterolobosea); Nuclearia sp. and Parvularia sp. (Nucleariidea, Cristidiscoidea); and Vannella sp. (Discosea, Amoebozoa). Phylogenetic analyses suggest that these four species independently evolved from mesophilic and neutrophilic ancestors, separate from each other. Additionally, Platyophrya sp. (Colpodea, Ciliophora) and two species of Neobodo (Euglenozoa, Kinetoplastea) were also found in the same environment, while their maximum survival temperatures were 35°C and 30°C, respectively. Among these, all species except Neobodo were confirmed to grow exclusively by feeding on Cyanidiococcus sp., a dominant species of Cyanidiophyceae in the environment. Thus, various lineages of heterotrophic unicellular eukaryotes have independently developed acidophilic and thermotolerant traits, allowing them to colonize sulfuric hot springs.

  • A fusion protein of polyphosphate kinase 1 (PPK1) and a Nudix hydrolase is involved in inorganic polyphosphate accumulation in the unicellular red alga Cyanidioschyzon merolae.

    Yagisawa F, Fujiwara T, Yamashita S, Hirooka S, Tamashiro K, Izumi J, Kanesaki Y, Onuma R, Misumi O, Nakamura S, Yoshikawa H, Kuroiwa H, Kuroiwa T, Miyagishima SY

    Plant molecular biology ( Springer Science and Business Media LLC )  115 ( 1 ) 9   2024.12 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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  • Development of a rapamycin-inducible protein-knockdown system in the unicellular red alga Cyanidioschyzon merolae.

    Fujiwara T, Hirooka S, Yamashita S, Yagisawa F, Miyagishima SY

    Plant physiology ( Oxford University Press (OUP) )  196 ( 1 ) 77 - 94   2024.06 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    Abstract An inducible protein-knockdown system is highly effective for investigating the functions of proteins and mechanisms essential for the survival and growth of organisms. However, this technique is not available in photosynthetic eukaryotes. The unicellular red alga Cyanidioschyzon merolae possesses a very simple cellular and genomic architecture and is genetically tractable but lacks RNA interference machinery. In this study, we developed a protein-knockdown system in this alga. The constitutive system utilizes the destabilizing activity of the FK506-binding protein 12 (FKBP12)-rapamycin-binding (FRB) domain of human target of rapamycin kinase or its derivatives to knock down target proteins. In the inducible system, rapamycin treatment induces the heterodimerization of the human FRB domain fused to the target proteins with the human FKBP fused to S-phase kinase-associated protein 1 or Cullin 1, subunits of the SCF E3 ubiquitin ligase. This results in the rapid degradation of the target proteins through the ubiquitin-proteasome pathway. With this system, we successfully degraded endogenous essential proteins such as the chloroplast division protein dynamin-related protein 5B and E2 transcription factor, a regulator of the G1/S transition, within 2 to 3 h after rapamycin administration, enabling the assessment of resulting phenotypes. This rapamycin-inducible protein-knockdown system contributes to the functional analysis of genes whose disruption leads to lethality.

  • Complete mitochondrial and chloroplast DNA sequences of the freshwater green microalga Medakamo hakoo.

    Takusagawa M, Misumi O, Nozaki H, Kato S, Maruyama S, Tsujimoto-Inui Y, Yagisawa F, Ohnuma M, Kuroiwa H, Kuroiwa T, Matsunaga S

    Genes & genetic systems ( 日本遺伝学会 )  98 ( 6 ) 353 - 360   2024.02

    Type of publication: Research paper (scientific journal)

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    <p>We report the complete organellar genome sequences of an ultrasmall green alga, <i>Medakamo hakoo</i> strain M-hakoo 311, which has the smallest known nuclear genome in freshwater green algae. <i>Medakamo hakoo</i> has 90.8-kb chloroplast and 36.5-kb mitochondrial genomes containing 80 and 33 putative protein-coding genes, respectively. The mitochondrial genome is the smallest in the Trebouxiophyceae algae studied so far. The GC content of the nuclear genome is 73%, but those of chloroplast and mitochondrial genomes are 41% and 35%, respectively. Codon usages in the organellar genomes have a different tendency from that in the nuclear genome. The organellar genomes have unique characteristics, such as the biased encoding of mitochondrial genes on a single strand and the absence of operon structures in chloroplast ribosomal genes. <i>Medakamo hakoo</i> will be helpful for understanding the evolution of the organellar genome and the regulation of gene expression in chloroplasts and mitochondria.</p>

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Books 【 display / non-display 】

  • Cyanidioschyzon merolae: A New Model Eukaryote for Cell and Organelle Biology

    Yagisawa F, Imoto Y, Fujiwara T, Miyagishima S ( Part: Multiple Authorship ,  16. Single-Membrane-Bound organelles: Division and Inheritance )

    Springer  2018.02

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Other Papers 【 display / non-display 】

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Grant-in-Aid for Scientific Research 【 display / non-display 】

  • Grant-in-Aid for Scientific Research(B)

    Project Year: 2022.04  -  2025.03 

  • Grant-in-Aid for Scientific Research(C)

    Project Year: 2022.04  -  2025.03 

    Direct: 3,200,000 (YEN)  Overheads: 960,000 (YEN) 

  • Molecular mechanisms and the functions of the membrane contact sites between mitochondria and lysosomes

    Grant-in-Aid for Scientific Research(C)

    Project Year: 2019.04  -  2022.03 

    Investigator(s): Yagisawa Fumi 

    Direct: 3,300,000 (YEN)  Overheads: 4,290,000 (YEN)  Total: 990,000 (YEN)

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    Lysosomes (vacuoles) play a role in intercellular degradation, and mitochondria are the primary sites for energy production. In simple unicellular red algae Cyanidioschyzon merolae, these compartments interact during mitosis. Previous studies show that the protein VIG1, a component of the ESCRT complex, mediates contact site formation. This study demonstrates that VIG1 functions in the interaction are independent of other ESCRT proteins. Additionally, we also found that ESCRT plays a role in cytokinetic abscission in C. merolae.

  • Elucidating the basis of plant cells based on the organelle division mechanism of microalgae

    Grant-in-Aid for Scientific Research(B)

    Project Year: 2019.04  -  2022.03 

    Investigator(s): KUROIWA Tsuneyoshi 

    Direct: 13,100,000 (YEN)  Overheads: 17,030,000 (YEN)  Total: 3,930,000 (YEN)

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    Dynamics of organelle division / proliferation, etc. in eukaryotic cell proliferation, and the mechanism that leads the information to the cell nucleus and cytokinesis was studied using the primitive red alga C. merolae as a material. Each organelle divides sequentially using a division device, and each division. The constituents of the device were confirmed. It was revealed that TOP (kinesin-like substance) acts on the distribution of divided organelles and then is involved in cell fission. Subsequently, the cell membrane contractile substance (EF1α) functioned, and then molecules involved in central cell membrane disruption (ESCRT-III, ALIX, VPS4, etc.) appeared and divided. ESCR-III was presumed to form a complex with an "electron-dense ring" and cause final fragmentation, and similar rings were also observed in Medakamo. In addition, a metaphase chromosomal structure was confirmed in Schyzon.

  • Uneven distribution of organelle proteins during binary fission of Cyanidioschyzon merolae

    Grant-in-Aid for challenging Exploratory Research

    Project Year: 2016.04  -  2018.03 

    Investigator(s): YAGISAWA Fumi, FUJIWARA Takayuki 

    Direct: 2,900,000 (YEN)  Overheads: 3,770,000 (YEN)  Total: 870,000 (YEN)

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    Eukaryotic cells such as animal stem cells and budding yeast divide into two daughter cells with different life spans. In these cells, organelle distribution is asymmetric regarding its quality; for example, young mitochondria are selectively distributed to cells with longer life spans. Such asymmetrical sorting of organelles is considered to be important for maintaining stemness, keeping one daughter cell young. In this project, we addressed whether similar phenomena may exist in cells that apparently divide symmetrically. Using the unicellular red alga Cyanidioschyzon merolae that proliferates through binary fission, we found that peroxisome inheritance is asymmetrical in terms of its quality. We also developed molecular tools to elucidate mechanisms associated with this phenomenon.

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