DNA複製がない場合の転写サイレンシングの確立

Y C Li¹, T H Cheng, M R Gartenberg

¹Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.

Science (New York, N.Y.)

|February 7, 2001

まとめ

酵母における転写サイレンシングを確立するために,DNA複製は必要ありません. 静止は,複製しないDNAで起こり,この重要な細胞サイクルプロセスに関する以前の仮定に挑戦します.

科学分野:

分子生物学は分子生物学である.
イースト遺伝学イースト遺伝学
エピジェネティクスエピジェネティクス

背景:

Saccharomyces cerevisiaeの交配型ロシの転写静止は,酵母細胞のタイプ決定に不可欠です.
この静音化プロセスは,細胞サイクルが制御する確立段階に依存することが知られているが,しばしばDNA複製が関与すると推定されている.

研究の目的:

イーストの交配型ロシウムでの静止の確立におけるDNA複製の直接的な役割を調査する.
DNA複製がない場合にサイレンシングが確立できるかどうかを判断する.

主な方法:

非複製の円形DNA分子 (リング) を生成するためにサイト固有の再結合を利用した. in vivo.
静音化因子Sir1をDNAリングに繋げて静音化器を起動した.
静止DNAリングの構造的特徴を分析し,DNAスーパーコイルとヒストンアセチル化レベルを含む.

主要な成果:

複製をしないDNAに転写サイレンシングが確立できることを実証しました.
沈黙されたDNAリングは,変化したスーパーコイリングと減少したヒストンアセチル化などの本物のサイレントクロマチンの特徴を示した.
静音化の確立には,静音化因子Sir2,Sir3,Sir4の存在が必要であり,細胞周期の初期のSとM段階の間に発生した.

結論:

複製フォークの通過は,酵母菌の静音化を確立するために必要な細胞サイクルイベントではありません.
これらの発見は,DNA複製と沈黙の確立を結びつける長年の仮定に異議を唱える.
静かなクロマチンの形成を媒介する細胞サイクルに依存する代替メカニズムを示唆している.

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