メタステーブルな転写因子-核細胞複合体による核細胞核の移転 in vitro

J L Workman¹, R E Kingston

¹Department of Molecular Biology, Massachusetts General Hospital, Boston 02114.

Science (New York, N.Y.)

|December 11, 1992

まとめ

GAL4のような転写因子は,DNA結合構造であるヌクレオソームを位移させることができます. この発見は,DNAのアクセシビリティを変更することによって,遺伝子調節のためのメカニズムを明らかにします.

科学分野:

分子生物学は分子生物学である.
エピジェネティクスエピジェネティクス
クロマチンのダイナミクス

背景:

転写因子は,特定のDNA配列に結合することによって遺伝子発現を調節する.
染色体構造,特に核細胞は,転写因子のDNAへのアクセスを妨げる可能性があります.
転写因子がクロマチンの障壁を克服する方法を理解することは,遺伝子調節にとって極めて重要です.

研究の目的:

転写因子が核個体と相互作用し,潜在的に核個体を置換するメカニズムを調査する.
DNA結合ドメインのみが核細胞の不安定化に十分であるかどうかを判断する.

主な方法:

イーストのGAL4タンパク質のDNA結合ドメインをモデル転写因子として利用した.
孤立した核細胞核粒子との GAL4 の相互作用を研究した.
競争相手のDNAを用いて,結果の複合体の安定性を評価した.

主要な成果:

GAL4が核細胞核粒子に結合すると,ヒストンとDNAを含む不安定な三元複合体を形成します.
この複合体は,競合するDNAを添加すると解離し,自由ヌクレオソームまたは裸のDNAに結合したGAL4を生成します.
GAL4による核分子の不安定化は,その転写活性化領域に依存しなかった.

結論:

GAL4のような調節因子は,DNAから核細胞核を直接異動させることができます.
この異位メカニズムは,活体内でプロモーターとエンハンスターに転写因子結合を確立するために重要な役割を果たす可能性があります.
発見は,転写因子とクロマチンの構造の間のダイナミックな相互作用の洞察を提供します.

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