芽生える酵母におけるクロマチンの境界:核毛孔接続

Kojiro Ishii¹, Ghislaine Arib, Clayton Lin

¹Departments of Biochemistry and Molecular Biology, University of Geneva, 30, Quai Ernest-Ansermet, Geneva, Switzerland.

Cell

|June 14, 2002

まとめ

核輸送タンパク質は,酵母におけるクロマチンの境界要素として作用し,ヘテロクロマチンの拡散を防止し,遺伝子発現を維持するために,遺伝子を核毛孔複合体と結び付けます.

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
イースト遺伝学イースト遺伝学

背景:

染色体境界活動 (BAs) は,静止から遺伝子を隔離する領域を定義します.
Saccharomyces cerevisiaeの静かな交配型ロカスHMLは,ヘテロクロマチン形成と境界要素の研究のモデルである.
核輸送に関与するタンパク質は,正規の機能を超えた役割としてますます認識されています.

研究の目的:

Saccharomyces cerevisiae.における新しいクロマチンの境界活性を特定し,特徴づけること.
エピジェネティック調節における核-細胞質輸送タンパク質の役割を調査する.
輸送タンパク質がHMLロカスで境界活動を確立するメカニズムを解明する.

主な方法:

境界活動を特定するための遺伝子スクリーニング.
タンパク質の局所化を追跡するために,免疫局所化と生細胞イメージングを行う.
DNAとタンパク質の相互作用を評価するためのクロマチンの免疫プレシピテーション (ChIP).
遺伝子削除や標的型DNA要素の改変を含む遺伝子操作.

主要な成果:

エクスポートインCse1p,Mex67p,Los1pを含むいくつかの核細胞質輸送タンパク質は,クロマチンの境界活性を示しています.
これらの輸送タンパク質は,HMLロカスと核孔複合体 (NPC) のNup2p受容体に物理的に結合します.
NUP2の削除は,これらの輸送タンパク質の境界活性を取り除き,DNAへの標的の結合は,それを回復します.

結論:

核輸送タンパク質によるゲノムロシのNPCへの物理的結合は,クロマチンの境界を確立することができます.
このメカニズムは,ヘテロクロマチンの拡散を防止し,それによって活性な転写状態を維持します.
核毛孔複合体の成分は,遺伝子発現の表遺伝的調節に直接的な役割を果たします.

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