ゲノム複製開始点の2重鎖DNAを特異的に開裂する蛋白質高次複合体のメカニズム
キーワード:ゲノム複製、細胞周期、DnaA蛋白質、AAA+ファミリー
2005.10.
尾﨑 省吾(おざき しようご) | データ更新日:2024.04.08 |
主な研究テーマ
研究業績
主要原著論文
1. | Chuyuan Lu, Ryusei Yoshida, Tsutomu Katayama, Shogo Ozaki, Thermotoga maritima oriC involves a DNA unwinding element with distinct modules and a DnaA-oligomerizing region with a novel directional binding mode, Journal of Biological Chemistry, 10.1016/j.jbc.2023.104888, 104888-104888, 2023.07, Initiation of chromosomal replication requires dynamic nucleoprotein complexes. In most eubacteria, the origin oriC contains multiple DnaA box sequences to which the ubiquitous DnaA initiators bind. In Escherichia coli oriC, DnaA boxes sustain construction of higher-order complexes via DnaA-DnaA interactions, promoting the unwinding of the DNA unwinding element (DUE) within oriC and concomitantly binding the single-stranded DUE to install replication machinery. Despite the significant sequence homologies among DnaA proteins, bacterial oriC sequences are highly diverse. The present study investigated the design of oriC (tma-oriC) from Thermotoga maritima, an evolutionarily ancient eubacterium. The minimal tma-oriC sequence includes a DUE and a flanking region containing five DnaA boxes recognized by the cognate DnaA initiator (tmaDnaA). This DUE was comprised of two distinct functional modules, an unwinding module and a tmaDnaA-binding module. Three direct repeats of the trinucleotide TAG within DUE were essential for both unwinding and single-stranded DUE binding by tmaDnaA complexes constructed on the DnaA boxes. Its surrounding AT-rich sequences stimulated only duplex unwinding. Moreover, head-to-tail oligomers of ATP-bound tmaDnaA were constructed within tma-oriC, irrespective of the directions of the DnaA boxes. This binding mode was considered to be induced by flexible swiveling of DnaA domains III and IV, which were responsible for DnaA-DnaA interactions and DnaA box binding, respectively. Phasing of specific tmaDnaA boxes in tma-oriC DNA was also responsible for unwinding. These findings indicate that a single-stranded DUE recruitment mechanism was responsible for unwinding, and would enhance understanding of the fundamental molecular nature of the origin sequences present in evolutionarily divergent bacteria.. |
2. | Shogo Ozaki, Dengyu Wang, Yasutaka Wakasugi, Naoto Itani, Tsutomu Katayama, The Caulobacter crescentus DciA promotes chromosome replication through topological loading of the DnaB replicative helicase at replication forks, Nucleic Acids Research, 10.1093/nar/gkac1146, 2022.12, Abstract The replicative DNA helicase translocates on single-stranded DNA to drive replication forks during chromosome replication. In most bacteria the ubiquitous replicative helicase, DnaB, co-evolved with the accessory subunit DciA, but how they function remains incompletely understood. Here, using the model bacterium Caulobacter crescentus, we demonstrate that DciA plays a prominent role in DNA replication fork maintenance. Cell cycle analyses using a synchronized Caulobacter cell population showed that cells devoid of DciA exhibit a severe delay in fork progression. Biochemical characterization revealed that the DnaB helicase in its default state forms a hexamer that inhibits self-loading onto single-stranded DNA. We found that upon binding to DciA, the DnaB hexamer undergoes conformational changes required for encircling single-stranded DNA, thereby establishing the replication fork. Further investigation of the functional structure of DciA revealed that the C-terminus of DciA includes conserved leucine residues responsible for DnaB binding and is essential for DciA in vivo functions. We propose that DciA stimulates loading of DnaB onto single strands through topological isomerization of the DnaB structure, thereby ensuring fork progression. Given that the DnaB-DciA modules are widespread among eubacterial species, our findings suggest that a common mechanism underlies chromosome replication.. |
3. | Shogo Ozaki, Yasutaka Wakasugi, Tsutomu Katayama, Z-Ring-Associated Proteins Regulate Clustering of the Replication Terminus-Binding Protein ZapT in Caulobacter crescentus, mBio, 10.1128/mBio.02196-20, 2021.01. |
4. | Shogo Ozaki, Urs Jenal, Tsutomu Katayama, Novel divisome-associated protein spatially coupling the z-ring with the chromosomal replication terminus in caulobacter crescentus, mBio, 10.1128/mBio.00487-20, 11, 2, 2020.03, [URL], Cell division requires proper spatial coordination with the chromosome, which undergoes dynamic changes during chromosome replication and segregation. FtsZ is a bacterial cytoskeletal protein that assembles into the Z-ring, providing a platform to build the cell division apparatus. In the model bacterium Caulobacter crescentus, the cellular localization of the Z-ring is controlled during the cell cycle in a chromosome replication-coupled manner. Although dynamic localization of the Z-ring at midcell is driven primarily by the replication origin-associated FtsZ inhibitor MipZ, the mechanism ensuring accurate positioning of the Z-ring remains unclear. In this study, we showed that the Z-ring colocalizes with the replication terminus region, located opposite the origin, throughout most of the C. crescentus cell cycle. Spatial organization of the two is mediated by ZapT, a previously uncharacterized protein that inter-acts with the terminus region and associates with ZapA and ZauP, both of which are part of the incipient division apparatus. While the Z-ring and the terminus region coin-cided with the presence of ZapT, colocalization of the two was perturbed in cells lacking zapT, which is accompanied by delayed midcellular positioning of the Z-ring. Moreover, cells overexpressing ZapT showed compromised positioning of the Z-ring and MipZ. These findings underscore the important role of ZapT in controlling cell division pro-cesses. We propose that ZapT acts as a molecular bridge that physically links the terminus region to the Z-ring, thereby ensuring accurate site selection for the Z-ring. Because ZapT is conserved in proteobacteria, these findings may define a general mechanism coordinating cell division with chromosome organization. IMPORTANCE Growing bacteria require careful tuning of cell division processes with dynamic organization of replicating chromosomes. In enteric bacteria, ZapA associates with the cytoskeletal Z-ring and establishes a physical linkage to the chromosomal replication terminus through its interaction with ZapB-MatP-DNA complexes. However, because ZapB and MatP are found only in enteric bacteria, it remains unclear how the Z-ring and the terminus are coordinated in the vast majority of bacteria. Here, we provide evidence that a novel conserved protein, termed ZapT, mediates colocalization of the Z-ring with the terminus in Caulobacter crescentus, a model organism that is phylo-genetically distant from enteric bacteria. Given that ZapT facilitates cell division processes in C. crescentus, this study highlights the universal importance of the physical linkage between the Z-ring and the terminus in maintaining cell integrity.. |
主要総説, 論評, 解説, 書評, 報告書等
主要学会発表等
学会活動
学協会役員等への就任
2024.01~2026.12, 日本ゲノム微生物学会, 幹事.
2024.01~2026.12, 日本ゲノム微生物学会, 評議員.
2023.08~2023.10, 日本ゲノム微生物学会, 選挙管理委員.
学会大会・会議・シンポジウム等における役割
2024.11.27~2024.11.27, 第47回日本分子生物学会年会 シンポジウム「Frontiers in microbial genome researches provide a fundamental insight into conserved and diverse nature of cell duplication systems」, オーガナイザー.
2024.03.28~2024.03.29, 2023年度国立遺伝学研究所研究会, 代表者.
2023.10.05~2023.10.05, 大隅基礎科学創成財団 微生物コンソーシアム G1第21回定例会, 座長.
2023.12.06~2023.12.08, 第46回日本分子生物学会年会 シンポジウム「Decoding the Universality of Cell Growth Principles in Microorganisms」, オーガナイザー.
2023.09.06~2023.09.08, 日本遺伝学会 第95回大会 ワークショップ「ユークリッド遺伝学:ポストDX時代の遺伝学から紐解く生命現象」, オーガナイザー.
2022.11.24~2022.11.24, 大隅基礎科学創成財団 微生物コンソーシアム 第6回 全体会, 世話人.
2022.09.14~2022.09.17, 日本遺伝学会 第94回大会 ワークショップ「バクテリアの細胞増殖研究から見えてくる遺伝学の新たな課題」, オーガナイザー.
2022.11.30~2022.12.02, 第45回日本分子生物学会年会 ワークショップ「NEXT微生物学」, オーガナイザー.
2021.09.08~2021.09.10, 日本遺伝学会 第93回大会, Best Papers賞審査委員.
2021.12.01~2021.12.03, 第44回日本分子生物学会年会 ワークショップ「微生物の生」, オーガナイザー.
2021.09.09~2021.09.09, 日本遺伝学会 第93回大会 一般講演, 座長.
2021.09.08~2021.09.10, 日本遺伝学会 第93回大会 ワークショップ「バクテリア研究の最前線から紐解く複製システムのモジュラリティ」, オーガナイザー.
2021.08.27~2021.08.27, The 6th Japan-Taiwan Joint Symposium for Pharmaceutical Sciences, Session Chair(the Session-4).
2021.06.12~2021.06.12, 令和3年度日本生化学会九州支部例会, 座長.
2021.03.04~2021.03.04, 国際ウェビナー"細胞複製システムの頑強性と可塑性", Organizer.
2021.03.04~2021.03.06, 第15回日本ゲノム微生物学会年会, 年会事務局・年会組織委員.
2020.02.19~2020.02.21, 第93回日本細菌学会総会シンポジウム「環状ヌクレオチド:細菌の増 殖とふるまいを制御する低分子シグナリングの機能と役割」, オーガナイザー.
2019.12.04~2019.12.04, 第42回日本分子生物学会年会ワークショップ「微生物の細胞複製原理を理解する」, オーガナイザー.
2019.11.09~2019.11.11, 第25回DNA複製・組換え・修復ワークショップ セッション2, 座長.
2018.11.28~2018.11.30, 第41回日本分子生物学会年会 ワークショップ「微生物の増殖とふるまいの複雑性:多様なモデル微生物系から到達する新たな理解」, オーガナイザー.
2018.03.05~2018.03.07, 第12回日本ゲノム微生物学会, 座長.
2018.09.19~2018.09.22, 日本遺伝学会 第90回大会 ワークショップ「多様なモデル原核生物の解析から見えてくる遺伝情報複製・継承の共通原理と多様性, オーガナイザー.
2018.06.30~2018.07.01, 平成30年度日本生化学会九州支部例会, 座長.
2011.05.18~2011.05.19, 第8回大腸菌研究会, 座長(Chairmanship).
その他の研究活動
海外渡航状況, 海外での教育研究歴
Paris-Saclay University, University of Basel, France, Switzerland, 2023.06~2023.06.
ナレスアン大学, Thailand, 2018.12~2018.12.
チュラロンコン大学, Thailand, 2018.07~2018.07.
受賞
研究奨励賞, 日本ゲノム微生物学会, 2023.03.
平成31年度科学技術分野の文部科学大臣表彰 若手科学者賞, 文部科学省, 2019.04.
若手優秀発表賞, 第24回DNA複製・組換え・修復ワークショップ運営委員会, 2017.11.
平成28年度日本分子生物学会 富澤純一・桂子 基金 若手賞, 日本分子生物学会, 2016.05.
平成23年 上原記念生命科学財団ポストドクトラルフェロー, 上原記念生命科学財団, 2011.03.
平成23年 持田記念医学薬学振興財団留学助成, 持田記念医学薬学振興財団, 2011.10.
日本遺伝学会第80回大会Best Papers賞, 日本遺伝学会, 2008.11.
日本遺伝学会第79回大会Best Papers賞, 日本遺伝学会, 2007.11.
研究資金
科学研究費補助金の採択状況(文部科学省、日本学術振興会)
2023年度~2025年度, 基盤研究(C), 代表, 染色体DNAへの複製ヘリカーゼ導入機構とその制御.
2018年度~2020年度, 基盤研究(B), 代表, 染色体の時空間情報と連係して細胞周期を制御する新たな分子複合体の解析.
2009年度~2010年度, 若手研究(B), 代表, 開始蛋白DnaAが形成する高次複合体のATP依存活性化メカニズム.
2007年度~2008年度, 特別研究員奨励費, 代表, ゲノム複製開始点の2重鎖DNAを特異的に開裂する蛋白質高次複合体のメカニズム.
科学研究費補助金の採択状況(文部科学省、日本学術振興会以外)
2018年度~2020年度, 厚生労働科学研究費補助金 (厚生労働省), 代表, 細菌バイオフィルムを選択的に阻害する薬剤開発の新規アプローチ.
日本学術振興会への採択状況(科学研究費補助金以外)
2013年度~2014年度, 海外特別研究員, 代表, 真正細菌の細胞周期制御:ゲノムの適時的複製開始メカニズム.
2007年度~2008年度, 特別研究員, 代表, ゲノム複製開始点の2重鎖DNAを特異的に開裂する蛋白質高次複合体のメカニズム.
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