Updated on 2026/06/17

写真a

 
WATANABE MAI
 
Organization
Undergraduate School School of Agriculture Assistant Professor (non-tenured)
Title
Assistant Professor (non-tenured)
Contact information
メールアドレス
External link

Research Interests

  • supercomplex

  • phycobilisome

  • Photosynthesis

  • antenna

Papers

  • Comparative study of phycoerythrobilin synthases for fine-tuning photosynthetic light-harvesting complexes, phycobilisomes

    Mizuho Sato, Mai Watanabe, Misaki Iwata, Kaisei Maeda, Kaori Nimura-Matsune, Masahiko Ikeuchi, Rei Narikawa, Satoru Watanabe

    Scientific Reports   2026.4

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    Abstract

    Phycobilisomes serve as the major light-harvesting antenna complexes in cyanobacteria; they capture light and transfer excitation energy to the photosystems, and their spectral and functional properties are primarily determined by the types of bilin chromophores attached to phycobiliproteins. We previously revealed that the properties of phycobilisomes can be modulated by altering the biosynthesis of these bilin chromophores. In this study, we introduced two distinct phycoerythrobilin (PEB) biosynthetic enzymes, pcyX and pebS , into the cyanobacterium Synechococcus elongatus PCC 7942 and successfully enabled PEB incorporation into native phycobilisomes. PebS exhibited high PEB synthesis activity comparable to the canonical PebA-PebB pathway, whereas PcyX showed lower activity, enabling fine-tuning of PEB accumulation. Consistent with previous findings, moderate PEB supply enhanced growth under green light; notably, PcyX expression further promoted growth by providing a more balanced pigment supply. Transcriptome analysis confirmed comparable expression of pebA - pebB , pcyX , and pebS , and revealed that increased PEB accumulation triggered broad metabolic remodeling: genes for glucose metabolism, hydrogenase complexes, potassium transporters, and regulatory factors including sigma factors were upregulated, suggesting a shift toward dissipation of excess reducing power. Together, these findings demonstrate that engineering bilin biosynthesis modifies light-harvesting properties and influences cellular metabolic balance, illustrating the potential of pigment pathway manipulation for redesigning photosynthetic function.

    DOI: 10.1038/s41598-026-50582-3

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  • CurT/CURT1 proteins are involved in cell and chloroplast division coordination of cyanobacteria and green algae

    Marcel Dann, Eunchul Kim, Konomi Fujimura-Kamada, Vjosa Berisha, Mami Nomura, Anne-Christin Pohland, Mai Watanabe, Matthias Ostermeier, Frederik Sommer, Michael Schroda, Shin-ya Miyagishima, Jun Minagawa

    Nature Communications   2025.9

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41467-025-64163-x

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  • Functional Modification of Cyanobacterial Phycobiliprotein and Phycobilisomes through Bilin Metabolism Control. International journal

    Mizuho Sato, Takeshi Kawaguchi, Kaisei Maeda, Mai Watanabe, Masahiko Ikeuchi, Rei Narikawa, Satoru Watanabe

    ACS synthetic biology   13 ( 8 )   2391 - 2401   2024.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    Phycobilisomes (PBSs) are light-harvesting antenna complexes in cyanobacteria that adapt to diverse light environments through the use of phycobiliproteins within the PBS structures. Freshwater cyanobacteria, such as Synechococcus elongatus PCC 7942, thrive under red light because of the presence of phycocyanin (PC) and its chromophore, phycocyanobilin (PCB), in the PBS. Cyanobacteria in shorter-wavelength light environments such as green light, employ phycoerythrin paired with phycoerythrobilin (PEB) along with PC in the PBS. Synthetic biology studies have shown that PEB production can be achieved by expression of the heterologous PEB synthases 15,16-dihydrobiliverdin:ferredoxin oxidoreductase (PebA) and PEB:ferredoxin oxidoreductase (PebB), leading to PEB accumulation and cellular browning. This approach is genetically unstable, and the properties of the resulting PEB-bound PBS complexes remain uncharacterized. In this study, we engineered a novel strain of Synechococcus 7942 PEB1 with finely tuned control of PEB biosynthesis. PEB1 exhibited a reversible change in the color of the culture from green to brown and pink based on PebA and PebB induction levels. High induction led to complete PCB-to-PEB substitution, causing the disassembly of the PBS rod complex. In contrast, low induction levels of PebA and PebB resulted in the formation of a stable chimeric PBS complex with partial PCB-to-PEB substitution. This acclimation enabled efficient light harvesting in the green spectrum and energy transfer to the photosynthetic reaction center. These findings, which improve our understanding of PBS and highlight the structural importance of the bilin composition, provide a foundation for future studies on PBS adaptation in bioengineering, synthetic biology, and renewable energy.

    DOI: 10.1021/acssynbio.4c00094

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  • Functional Modification of Cyanobacterial Phycobiliprotein and Phycobilisomes through Bilin Metabolism Control

    Mizuho Sato, Takeshi Kawaguchi, Kaisei Maeda, Mai Watanabe, Masahiko Ikeuchi, Rei Narikawa, Satoru Watanabe

    ACS Synthetic Biology   13 ( 8 )   2391 - 2401   2024.7

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    Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society (ACS)  

    DOI: 10.1021/acssynbio.4c00094

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  • The organization of the phycobilisome-photosystem I supercomplex depends on the ratio between two different phycobilisome linker proteins

    Mai Watanabe, Masahiko Ikeuchi, Annegret Wilde

    Photochemical & Photobiological Sciences   2023.7

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s43630-023-00397-2

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  • Diverse Chromatic Acclimation Processes Regulating Phycoerythrocyanin and Rod-Shaped Phycobilisome in Cyanobacteria

    Hirose, Yuu, Chihong, Song, Watanabe, Mai, Yonekawa, Chinatsu, Murata, Kazuyoshi, Ikeuchi, Masahiko, Eki, Toshihiko

    Molecular plant   12 ( 5 )   715 - 725   2019

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    Publishing type:Research paper (scientific journal)   Publisher:Cell Press  

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  • Solar-panel and parasol strategies shape the proteorhodopsin distribution pattern in marine Flavobacteriia

    Kumagai, Yohei, Yoshizawa, Susumu, Nakajima, Yu, Watanabe, Mai, Fukunaga, Tsukasa, Ogura, Yoshitoshi, Hayashi, Tetsuya, Oshima, Kenshiro, Hattori, Masahira, Ikeuchi, Masahiko a

    The ISME journal   12 ( 5 )   1329 - 1329   2018

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    Publishing type:Research paper (scientific journal)   Publisher:Nature Publishing Group  

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  • High myristic acid content in the cyanobacterium Cyanothece sp. PCC 8801 results from substrate specificity of lysophosphatidic acid acyltransferase

    Saito, Masakazu, Endo, Kaichiro, Kobayashi, Koichi, Watanabe, Mai, Ikeuchi, Masahiko, Murakami, Akio, Murata, Norio, Wada, Hajime

    Biochimica et Biophysica Acta (BBA)-Molecular and Cell Biology of Lipids   1863 ( 9 )   939 - 947   2018

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier  

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  • The Non-Mendelian Green Cotyledon Gene in Soybean Encodes a Small Subunit of Photosystem II

    Kaori Kohzuma, Yutaka Sato, Hisashi Ito, Ayako Okuzaki, Mai Watanabe, Hideki Kobayashi, Michiharu Nakano, Hiroshi Yamatani, Yu Masuda, Yumi Nagashima, Hiroyuki Fukuoka, Tetsuya Yamada, Akira Kanazawa, Keisuke Kitamura, Yutaka Tabei, Masahiko Ikeuchi, Wataru Sakamoto, Ayumi Tanaka, Makoto Kusaba

    Plant Physiology   173 ( 4 )   2138 - 2147   2017.4

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    Publishing type:Research paper (scientific journal)   Publisher:American Society of Plant Biologists ({ASPB})  

    DOI: 10.1104/pp.16.01589

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  • PCoM-DB Update: A Protein Co-Migration Database for Photosynthetic Organisms Reviewed

    Atsushi Takabayashi, Saeka Takabayashi, Kaori Takahashi, Mai Watanabe, Hiroko Uchida, Akio Murakami, Tomomichi Fujita, Masahiko Ikeuchi, Ayumi Tanaka

    PLANT AND CELL PHYSIOLOGY   58 ( 1 )   2017.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/pcp/pcw219

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  • Characterization of the genuine type 2 chromatic acclimation in the two Geminocystis cyanobacteria

    Hirose, Yuu, Misawa, Naomi, Yonekawa, Chinatsu, Nagao, Nobuyoshi, Watanabe, Mai, Ikeuchi, Masahiko, Eki, Toshihiko

    DNA Research   24 ( 4 )   387 - 396   2017

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    Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press  

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  • CyanoBase: a large-scale update on its 20th anniversary

    Fujisawa, Takatomo, Narikawa, Rei, Maeda, Shin-ichi, Watanabe, Satoru, Kanesaki, Yu, Kobayashi, Koichi, Nomata, Jiro, Hanaoka, Mitsumasa, Watanabe, Mai, Ehira, Shigeki and

    Nucleic acids research   45 ( D1 )   D551 - D554   2016

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    Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press  

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  • Klebsormidium flaccidum genome reveals primary factors for plant terrestrial adaptation. Reviewed International journal

    Koichi Hori, Fumito Maruyama, Takatomo Fujisawa, Tomoaki Togashi, Nozomi Yamamoto, Mitsunori Seo, Syusei Sato, Takuji Yamada, Hiroshi Mori, Naoyuki Tajima, Takashi Moriyama, Masahiko Ikeuchi, Mai Watanabe, Hajime Wada, Koichi Kobayashi, Masakazu Saito, Tatsuru Masuda, Yuko Sasaki-Sekimoto, Kiyoshi Mashiguchi, Koichiro Awai, Mie Shimojima, Shinji Masuda, Masako Iwai, Takashi Nobusawa, Takafumi Narise, Satoshi Kondo, Hikaru Saito, Ryoichi Sato, Masato Murakawa, Yuta Ihara, Yui Oshima-Yamada, Kinuka Ohtaka, Masanori Satoh, Kohei Sonobe, Midori Ishii, Ryosuke Ohtani, Miyu Kanamori-Sato, Rina Honoki, Daichi Miyazaki, Hitoshi Mochizuki, Jumpei Umetsu, Kouichi Higashi, Daisuke Shibata, Yuji Kamiya, Naoki Sato, Yasukazu Nakamura, Satoshi Tabata, Shigeru Ida, Ken Kurokawa, Hiroyuki Ohta

    Nature communications   5   3978 - 3978   2014.5

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    Language:English   Publishing type:Research paper (scientific journal)  

    The colonization of land by plants was a key event in the evolution of life. Here we report the draft genome sequence of the filamentous terrestrial alga Klebsormidium flaccidum (Division Charophyta, Order Klebsormidiales) to elucidate the early transition step from aquatic algae to land plants. Comparison of the genome sequence with that of other algae and land plants demonstrate that K. flaccidum acquired many genes specific to land plants. We demonstrate that K. flaccidum indeed produces several plant hormones and homologues of some of the signalling intermediates required for hormone actions in higher plants. The K. flaccidum genome also encodes a primitive system to protect against the harmful effects of high-intensity light. The presence of these plant-related systems in K. flaccidum suggests that, during evolution, this alga acquired the fundamental machinery required for adaptation to terrestrial environments.

    DOI: 10.1038/ncomms4978

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  • Attachment of phycobilisomes in an antenna--photosystem I supercomplex of cyanobacteria

    Watanabe, Mai, Semchonok, Dmitry A., Webber-Birungi, Mariam T., Ehira, Shigeki, Kondo, Kumiko, Narikawa, Rei, Ohmori, Masayuki, Boekema, Egbert J., Ikeuchi, Masahiko

    Proceedings of the National Academy of Sciences   111 ( 7 )   2512 - 2517   2014

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    Publishing type:Research paper (scientific journal)   Publisher:National Academy of Sciences  

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  • Phycobilisome: architecture of a light-harvesting supercomplex

    Watanabe, Mai, Ikeuchi, Masahiko

    Photosynthesis research   116 ( 2-3 )   265 - 276   2013

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Netherlands  

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  • Supercomplex Organizations and Evolution of Photosystems I and II (Anabaena sp. PCC 7120, Cyanophora Paradoxa and Cyanidioschyzon Merolae)

    Watanabe, Mai, Kubota, Hisako, Wada, Hajime, Narikawa, Rei, Ikeuchi, Masahiko

    Photosynthesis Research for Food, Fuel and the Future   13 - 16   2013

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    Publisher:Springer, Berlin, Heidelberg  

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  • Phycobilisome model with novel skeleton-like structures in a glaucocystophyte Cyanophora paradoxa

    Watanabe, Mai, Sato, Momoko, Kondo, Kumiko, Narikawa, Rei, Ikeuchi, Masahiko

    Biochimica et Biophysica Acta (BBA)-Bioenergetics   1817 ( 8 )   1428 - 1435   2012

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier  

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  • Novel supercomplex organization of photosystem I in Anabaena and Cyanophora paradoxa

    Watanabe, Mai, Kubota, Hisako, Wada, Hajime, Narikawa, Rei, Ikeuchi, Masahiko

    Plant and cell physiology   52 ( 1 )   162 - 168   2010

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    Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press  

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  • Is the photosystem II complex a monomer or a dimer?

    Watanabe, Mai, Iwai, Masako, Narikawa, Rei, Ikeuchi, Masahiko

    Plant and cell physiology   50 ( 9 )   1674 - 1680   2009

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    Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press  

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  • Photosystem I complexes associated with fucoxanthin-chlorophyll-binding proteins from a marine centric diatom, Chaetoceros gracilis

    Ikeda, Yohei, Komura, Masayuki, Watanabe, Mai, Minami, Chie, Koike, Hiroyuki, Itoh, Shigeru, Kashino, Yasuhiro, Satoh, Kazuhiko

    Biochimica et Biophysica Acta (BBA)-Bioenergetics   1777 ( 4 )   351 - 361   2008

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier  

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  • Reconstitution of Cyclic Electron Transport in Synechocystis sp. PCC 6803 by a Cell-Free System

    Watanabe, Mai, Kashino, Yasuhiro, Satoh, Kazuhiko, Koike, Hiroyuki, Tsimilli-Michael, Merope, Strasser, Reto J.

    Photosynthesis. Energy from the Sun   703 - 707   2008

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    Publisher:Springer, Dordrecht  

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MISC

  • Leptolyngbya属シアノバクテリアの光合成装置の光色応答の解析

    広瀬侑, 長尾信義, 米川千夏, 渡辺麻衣, 池内昌彦, 浴俊彦

    日本ゲノム微生物学会年会要旨集   11th   2017

Research Projects

  • 集光性アンテナの構造と機能の1分子相関観察

    Grant number:24H00872  2024.4 - 2027.3

    日本学術振興会  科学研究費助成事業  学術変革領域研究(B)

    渡辺 麻衣, 藤芳 暁

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    Grant amount:\52130000 ( Direct Cost: \40100000 、 Indirect Cost:\12030000 )

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  • Elucidation of Cellular Function and Evolution through Restorative Approach: Reconstruction of Photosynthetic Antenna Complexes

    Grant number:24H00869  2024.4 - 2027.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Transformative Research Areas (B)

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    Grant amount:\3120000 ( Direct Cost: \2400000 、 Indirect Cost:\720000 )

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  • 光化学系Iの2つのアンテナタンパク質の機能分化から解き明かす光エネルギー分配原理

    Grant number:20J40231  2020.10 - 2024.3

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    渡辺 麻衣

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    Grant amount:\4030000 ( Direct Cost: \3100000 、 Indirect Cost:\930000 )

    窒素欠乏条件下ではCpcLのタンパク質量の増加と、CpcG4のタンパク質量の減少が見られ、PBS-CpcL-PSI超複合体が増加する。また、RNA-seq解析において窒素欠乏条件下でcpcLの発現が上昇することが報告されている。そこで、窒素欠乏時におけるcpcLとcpcG4の転写量をノザンブロッティングにより調べた。その結果、窒素欠乏時におけるcpcLの発現レベルの減少はcpcG4に比べて抑えられていることがわかった。これにより、窒素欠乏時のCpcL/CpcG4のタンパク質量比が増加すると考えられる。cpcL、cpcG4遺伝子はゲノム上でcpcオペロンの一部として存在している。そのため、cpcL、cpcG4の転写ををそれぞれ個別に制御することは容易ではない。ノザンブロッティングの結果とRNA-seq解析の結果から、cpcオペロンには複数のプロモーターが存在することがわかった。その多くは窒素欠乏時に活性が低下する一方、cpcLのプロモーターのみ窒素欠乏時にも転写が活性化されていた。cpcLの隣の遺伝子はcpcG4であり、cpcLプロモーターによる転写によりcpcL-cpcG4転写産物が存在した。ノザンブロッティングの結果、cpcL 単独の転写産物は窒素欠乏時にも減少しないが、cpcL-cpcG4 転写産物は窒素欠乏により減少した。これは、cpcG4の転写を特異的に抑制する機構の存在を示唆する。RNA-seq解析の結果を精査することで、cpcG4がアンチセンスRNA(ascpcG4)によって制御を受けている可能性を見出し、ノザンブロッティングによりascpcG4の転写が窒素欠乏時のみで起きていることを示した。
    窒素欠乏時のcpcL、ascpcG4の転写が窒素固定細胞であるヘテロシスト特異的に起きているのかを検証するため、蛍光タンパク質によるレポーターアッセイを準備している。

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  • シアノバクテリアの光化学系Iへの光エネルギー分配の分子機構と生理的役割の解明

    Grant number:17H05716  2017.4 - 2019.3

    日本学術振興会  科学研究費助成事業 新学術領域研究(研究領域提案型)  新学術領域研究(研究領域提案型)

    榎本 麻衣

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    Grant amount:\6240000 ( Direct Cost: \4800000 、 Indirect Cost:\1440000 )

    本研究は、シアノバクテリアにおける光化学系Iへの光エネルギー分配の分子機構と生理的役割の解明を目指す。光化学系I複合体は、直鎖状と環状の二つの電子伝達系の両方に関わる。光化学系Iへの光エネルギー分配調節による活性制御は、光合成の調節に必要不可欠である。シアノバクテリアのアンテナタンパク質フィコビリソームは、主に光化学系IIへのエネルギー伝達を行う。一方、光化学系I特異的アンテナは知られていなかった。これまでに、光化学系Iと特異的アンテナとの超複合体の単離に成功し、光化学系I特異的アンテナ(CpcL-フィコビリソーム)の存在を生化学的に明らかにした。また、ドッキング因子CpcLを同定した。CpcLは、ロッド状のフィコビリソームを形成しロッドを直接光化学系Iに繋ぐ。本研究はCpcLを手がかりとし、シアノバクテリアの光エネルギー捕集、分配メカニズムを解明することを目的とする。
    cpcL過剰発現株および従来型のフィコビリソームのサブユニットであるcpcGの破壊株ではCpcL-フィコビリソームと光化学系Iの超複合体の量が野生株より増加する。cpcLとcpcGの発現量の比がCpcL-フィコビリソームと光化学系Iの超複合体の量を調節していると考えた。光化学系Iによる環状電子伝達が必要不可欠である窒素枯渇条件では、CpcL-フィコビリソームと光化学系Iの超複合体の量が増加する。その細胞における、cpcLとcpcGのRNA量をノザンブロッティングにより調べた。その結果、cpcLとcpcGのどちらも窒素欠乏時に発現が増加していた。また、cpcGが窒素欠乏時に発現するアンチセンスRNAによって転写後制御を受けている可能性を見出した。今後、cpcGのアンチセンスRNAによる転写後制御の実態を解析し、CpcL/CpcGのタンパク質量比の調節機構を明らかにする。

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