CENP-Bは,レトロトランポゾンLTRによって停止された複製フォークでゲノムの完全性を保ちます
Mikel Zaratiegui1, Matthew W Vaughn, Danielle V Irvine
1Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA.
Nature
|December 15, 2010
まとめ
セントロメア結合タンパク質B (CENP-B) は,LTRレトロトランポゾンを通してDNA複製フォークの進行を促進します. CENP-Bの喪失は,複製フォークの阻害によりゲノムの不安定性を引き起こし,ゲノム安定性の維持におけるその役割を強調します.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- エピジェネティクス エピジェネティクス
背景:
- セントロメア結合タンパク質B (CENP-B) は,ヘテロクロマチンとセントロメア重複に関連した保存されたDNA結合因子です.
- 核分裂酵母におけるCENP-Bホモログは,ヒストン脱酸化酵素を介してLTRレトロトランポゾンを沈黙させる.
- DNA複製におけるCENP-Bの説明できない役割が指摘されています.
研究 の 目的:
- DNA複製におけるCENP-Bの分子機能を明らかにする.
- LTRレトロトランポゾンによる複製フォークの進行におけるCENP-Bの役割を調査する.
- CENP-B変異体におけるゲノム不安定性の根底にあるメカニズムを理解する.
主な方法:
- 分裂酵母モデルを用いたDNA複製におけるCENP-B機能の分析.
- レプリケーション・フォーク・ダイナミクスと,LTR配列におけるブロックの調査.
- CENP-B変異体におけるゲノム不安定性とDNA再編成の評価.
- CENP-B,LTRs,DNA結合因子Sap1.1との相互作用に関する研究.
主要な成果:
- CENP-Bは,LTR配列を通してレプリケーションフォークの進行を積極的に促進します.
- CENP-Bが欠けている変異体は,複製フォークの阻害によるゲノム不安定性の増加を示しています.
- 複製フォークの阻害は,LTRsによって採用されたスイッチ活性化タンパク質1 (Sap1) に依存しています.
- Sap1媒介のバリア活性を失うと,フォークの進行は阻害されないが,有害なレトロトランポゾン再編成を引き起こす.
結論:
- CENP-Bは,LTR媒介の複製フォークの阻害に対抗し,フォークの安定性を促進します.
- レトロトランポゾンは,複製フォークブロックの近くにSap1を勧誘することで,複製極性に影響します.
- この発見は,脆弱な部位におけるLTRの役割と,CENP-Bがペリコントロメリックヘテロクロマチンとの関連性を説明する可能性がある.
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