SWR1によるヒストンの段階的な置換には,ヒストンH2A.Zと正規のヌクレオソームとの二重活性化が必要です
Ed Luk1, Anand Ranjan, Peter C Fitzgerald
1Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. luked@mail.nih.gov
Cell
|November 30, 2010
まとめ
SWR1複合体は,プロモーターのヒストンH2AをH2A.Zに置き換えます. この研究は,SWR1を明らかにしています.
科学分野:
- * 分子生物学 * 分子生物学
- * エピジェネティクス
- *クロマチンの生物学
背景:
- * ヒストン変種H2A.Zは,真核細胞のプロモーター調節に不可欠です.
- * SWR1複合体は,ATP依存ヒストン交換を通じてH2A.Zの組み込みを促進する.
- *SWR1媒介によるH2A.Z堆積の正確なメカニズムは,まだ完全に理解されていません.
研究 の 目的:
- * SWR1複合体によるH2A.Z置換のメカニズムを解明する.
- * プロモーター領域におけるH2A.Z核細胞の異質性を調査する.
- * ヒストン交換におけるSWR1 ATPaseの活性性の役割を決定する.
主な方法:
- * 精製されたSWR1複合体と核細胞を用いたインビトロ生化学分析.
- * 核細胞組成の分析とヒストン変異ステキオメトリー.
- *異なる基質に対する反応におけるSWR1ATPアゼの活性に関する特徴.
主要な成果:
- * プロモーター近接核細胞は,H2A.Z含有量の有意な異質性を示しています.
- *SWR1触媒によるH2A.Z置換は段階的に発生し,異型および同型核細胞を形成する.
- * SWR1 ATPaseの活動は,H2Aを含む核細胞と自由のH2A.Z-H2B二重体によって刺激され,H2Aの排出とH2A.Zの堆積を誘導する.
結論:
- * SWR1複合体は,単方向,段階的なH2A.Z置換を媒介する.
- * H2A.Z 含有量の核群異質性は,プロモーター近接領域の特徴である.
- * H2Aを含む核細胞と自由のH2A.Z-H2B二重体との相互作用が,ヒストン交換におけるSWR1の特異性と機能を決定する.
関連する概念動画
Nucleosome Remodeling
Nucleosomes are the basic units of chromatin compaction. Each nucleosome consists of the DNA bound tightly around a histone core, which makes the DNA inaccessible to DNA binding proteins such as DNA polymerase and RNA polymerase. Hence, the fundamental problem is to ensure access to DNA when appropriate, despite the compact and protective chromatin structure.
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Spreading of Chromatin Modifications
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex.
Writers
The writer is an enzyme that can...
Writers
The writer is an enzyme that can...
Histone Modification
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Histone Modification
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone deacetylase,...
Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
The Nucleosome Core Particle
Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...


