バクテリアのレトロンは,ファグを防御する三重の毒素対毒素システムをコードする
Jacob Bobonis1,2, Karin Mitosch1, André Mateus1,3
1Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
Nature
|July 19, 2022
まとめ
レトロンは プロカリオットの遺伝子要素です 研究者らは,サルモネラ・タイフィムリウムのRetron-Sen2系が,自身の逆転写酵素-msDNA複合体によって中和される毒素 (RcaT) をコードし,抗菌素防御のための新しい三部位毒素-抗毒素系を明らかにすることを発見した.
科学分野:
- 微生物学
- 分子生物学
- 遺伝学
背景:
- レトロンは多重複製単一鎖DNA (msDNA) を合成するプロカリオットレトロエレメントである.
- レトロンの正確な生物学的機能と生理学的役割は,msDNA生物合成に関する広範な研究にもかかわらず,ほとんど不明のままである.
研究 の 目的:
- レトロン元素の機能,特に Salmonella enterica serovar Typhimuriumからのレトロン-Sen2を明らかにする.
- 新しく特定された毒素タンパク質RcaTとそのレトロンの逆転写酵素および msDNAとの相互作用を特徴づける.
- バクテリアの防御メカニズムにおける レトロンの役割を調査する
主な方法:
- レトロンでコードされたアクセサリー毒素タンパク質の識別と改名 RcaT
- リバーストランスクリプトーゼ-msDNA複合体によるRcaT中和メカニズムの特徴化.
- 毒素活性化-抑制結合 (TAC-TIC) の開発と応用
- レトロン毒素-抗毒素システムのトリガーとブロッカーとしてのファグ由来タンパク質の分析.
主要な成果:
- Retron-Sen2は,その逆転写酵素-msDNA複合体によって中和されるRcaTをコードし,三部位DNAを含む毒素-抗毒素システムを形成します.
- リバース・トランスクリプトーゼはRcaTを結合し,msDNAは抗毒素活性を提供し,msDNAの生物合成が妨害されたときに活性化されます.
- TAC- TICシステムは,mSDNAを改変することによってRcaTを活性化したり,RcaTを直接抑制したりするファグタンパク質を特定し,抗ファグ活性を示した.
結論:
- RcaTレトロンシステムは,三部位DNA調節された毒素-抗毒素システムの新しいクラスを表しています.
- これらのシステムは,中断感染の抗菌体防衛機構として機能します.
- リバーストランスクリプトーゼ-msDNA複合体は,抗毒素とファグタンパク質の活性センサーの両方で作用し,細菌の防御を調節します.
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