機能的に相互依存する活動による単一の場所での編集とメチル化
Mary Anne T Rubio1, Kirk W Gaston1,2, Katherine M McKenney1
1Department of Microbiology, Ohio State Biochemistry Program and The Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA.
Nature
|February 24, 2017
まとめ
核酸の化学的変異は極めて重要であるが,よく理解されていない. この研究は,シトシンメチレーションがトライパノソーマブルセイtRNAのデアミン化の前提条件であり,ゲノム安定性を説明していることを示しています.
科学分野:
- 分子生物学
- 生物化学
- 遺伝学
背景:
- 核酸には,塩基と砂糖に影響を与える100以上の化学的変化があります.
- ほとんどの核酸変異の生物合成経路は,ほとんど解明されていない.
- 複雑な改変経路または相互依存性を示唆する.
研究 の 目的:
- ユカリオットにおけるtRNAのサイトシン-ウリジン編集のメカニズムを調査する.
- 酵素活性における改変相互依存の役割を明らかにする.
- トリパノソーマ・ブルセイが 変異性デアミナーゼを持つにもかかわらず ゲノムの完全性を維持する方法を理解する.
主な方法:
- Trypanosoma brucei tRNAThrにおけるサイトシン32の改変を調査した.
- TRM140メチルトランスフェラーゼとADAT2/3デアミナーゼを含む精製された成分を用いて,酵素活性を再構成した.
- メチルトランスフェラーゼとデアミナーゼの共発は,酵素活性と変異性を評価する.
主要な成果:
- T. brucei tRNAThrのサイトシン32は,TRM140によって3-メチルサイトシン (m3C) にメチル化される.
- m3Cは,ADAT2/3による3メチルウリジン (m3U) への後の解毒の前提となる.
- TRM140とADAT2/3の共発はADAT2/3の変異性を抑制し,ゲノムの安定性を維持する.
結論:
- メチル化がデアミネーションに先行する改変相互依存のモデルが示されている.
- この連続的な改変経路は,T. bruceiにおける大量除菌の欠如を説明する.
- ヒトのAIDを含む変異性デアミナーゼの調節に関する洞察が得られる.
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