媒介体とコヘシンが遺伝子発現とクロマチンの構造を結びつける
Michael H Kagey1, Jamie J Newman, Steve Bilodeau
1Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, Massachusetts 02142, USA.
Nature
|August 20, 2010
まとめ
媒介体とコヘシン複合体は,マウス細胞の遺伝子プロモーターと強化剤を物理的に結びつける. Nipblによって促進されるこの接続は,遺伝子発現に不可欠な細胞特異のDNAループを形成する.
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:
- 転写因子は,コアクティベーターと転写機構と相互作用することによって,細胞特異の遺伝子発現をオーケストラ化します.
- 遺伝子の活性化メカニズム,特に強化剤と促進剤の間のDNAループ形成は,まだ完全に理解されていません.
研究 の 目的:
- 活性遺伝子のエンハンサーとコアプロモーターの結合におけるメディエーターとコヘシンの役割を調査する.
- 細胞特異的な遺伝子調節におけるDNAループ形成のメカニズムを解明する.
主な方法:
- コイムノプレシピテーションは,タンパク質複合体を検出するための測定法です.
- 染色体構成のキャプチャ技術でDNAループを分析する.
- ネズミの胚性幹細胞における遺伝子調節要素とのメディエーター,コヘシン,ニップブル関連性の分析.
主要な成果:
- メディエーターとコヘシンが,活性遺伝子の強化剤とコアプロモーターを物理的に,機能的に結びつけることが判明しました.
- コヘシン負荷因子Nipblは,プロモーターのメディエーター-コヘシン複合体と関連している.
- DNAループは,メディエーターとコヘシンが占有するエンハンサーとプロモーター領域の間に観察されました.
- 媒介体とコヘシンには,細胞型特異のプロモーターの占有率があり,異なる遺伝子発現プログラムと相関しています.
結論:
- 媒介体とコヘシンが,DNAループを通じてエンハンサー・プロモーターの結合を確立する上で重要な役割を果たします.
- 媒介体-コヘシン複合体による細胞型特異のDNAループの形成は,細胞特異の遺伝子発現を調節する重要なメカニズムである.
関連する概念動画
02:20Cohesins
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
02:20Cohesins
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
02:25Spreading 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...
02:32Histone 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,...
02:32Histone 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,...
02:38Heterochromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...