システインクランプドメインの選択的非メチル化CpGDNA認識メカニズム
Bo Duan1, Dihong Fu1, Chaoqun Zhang1
1Beijing Nuclear Magnetic Resonance Center, College of Chemistry and Molecular Engineering, and School of Life Sciences, Peking University, Beijing 100871, China.
Journal of the American Chemical Society
|May 13, 2021
まとめ
転写因子TCFとGEFタンパク質は,C-クランプの亜鉛指を使用して非メチル化DNAを結合する. CpGのメチル化は結合を阻害し,重要な表遺伝的調節メカニズムを明らかにする.
科学分野:
- エピジェネティクス
- 構造生物学
- 分子生物学
背景:
- CpGメチル化は重要な表遺伝子調節因子ですが,転写因子結合への影響は不明です.
- TCF (T細胞因子) とGEF (グルコーストランスポーター4強化因子) のような転写因子ファミリーは,遺伝子調節に不可欠です.
- これらの要因がDNAとどのように相互作用するかを理解することは,特にメチル化という文脈で,不可欠です.
研究 の 目的:
- TCFとGEFタンパク質が非メチル化DNAを選択的に結合する分子機構を解明する.
- 特定のDNA配列をC-クランプの亜鉛指領域で認識するための構造的基礎を決定する.
- これらのタンパク質のDNA結合性に対するCpGメチル化の効果を調査する.
主な方法:
- 核磁気共振 (NMR) スペクトロスコーピーは,ヒトのGEFファミリータンパク質 HDBP1 (C-clampHDBP1) のC-クランプドメインの構造をDNAと複合的に決定します.
- 人間のTCF1E (C-clampTCF1E) のDNA結合メカニズムを分析するためのホモロジーモデリング.
- 種間のDNA認識モチーフとその保存の分析
主要な成果:
- C-クランプドメインはユニークな亜鉛指折れを採用し",Arg·Trp-Lys-Lys"モチーフを通じてRCCGGDNA配列を結合する.
- CpGダイヌクレオチドは,タンパク質の骨格とサイドチェーンに水素結合を介して結合することが重要です.
- CpGのサイトをメチル化すると,タンパク質の結合が著しく減少または消滅する.
- ホモロジーモデリングは,TCF1EがRCCGC配列を好む"Arg·Arg-Lys-Lys"モチーフで同様のメカニズムを使用することを示した.
- 特定されたDNA認識モチーフは,GEFとTCFファミリーからヒトに保存されています.
結論:
- TCFとGEFのタンパク質は,C-クランプの亜鉛指ドメインを通して非メチル化CpGサイトを選択的に標的とする.
- これらの転写因子の結合を防ぐ分子スイッチとして作用します.
- このメカニズムは,非メチル化CpG結合タンパク質が表遺伝子調節のために使用する共通の戦略を強調しています.
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