ポリコンブ群のタンパク質複合体によるクロマチンの圧縮
Nicole J Francis1, Robert E Kingston, Christopher L Woodcock
1Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA.
Science (New York, N.Y.)
|November 30, 2004
まとめ
Polycomb Repressive Complex 1は,発達中の遺伝子を沈黙させるためにクロマチンを圧縮する. この圧縮は,核個体に依存するが,ヒストンの尾ではないが,身体のパターンを維持するために極めて重要です.
科学分野:
- 発達生物学 発達生物学とは
- エピジェネティクス エピジェネティクス
- 分子生物学は分子生物学である.
背景:
- ポリコンブ群のタンパク質は,発達中の身体のパターンを維持するために不可欠です.
- 彼らはホメオティックな遺伝子を沈黙させることでこれを達成しますが,その背後にあるメカニズムは議論の余地があります.
- 鍵となる仮説は,抑圧的な染色体構造が関与していることを示唆している.
研究 の 目的:
- ポリコンブ抑制複合体1 (PRC1) が遺伝子を静止させる構造的メカニズムを調査する.
- PRC1がクロマチンの構造を直接変えて転写抑制を達成するかどうかを判断する.
主な方法:
- 電子顕微鏡を用いて,PRC1がヌクレオソーム配列に及ぼす影響を視覚化しました.
- 実験では,核細胞とヒストンの尻尾がコンパクト化に必要なことを評価した.
- Posterior Sex Combs (PSC) の構造機能分析が行われました.
主要な成果:
- PRC1のコアコンポーネントは,ニュクレオソーム配列の有意な圧縮を誘発することが示されました.
- この圧縮効果には,核細胞の存在が必要ですが,ヒストンの尾は不要です.
- 各PRC1複合体は,約3つの核細胞をコンパクトにします.
- 遺伝子静音化に不可欠な後部性の特定の領域は,クロマチンの凝縮に決定的であることが判明しました.
結論:
- PRC1はクロマチンの構造を直接圧縮し,遺伝子サイレンシングの物理的基盤を提供します.
- PRC1によるクロマチンの圧縮は,核分裂体に依存するプロセスであり,ヒストンの尾から独立しています.
- この発見は,PRC1の遺伝子静止とクロマチンの圧縮活動を結びつけ,安定した表遺伝的調節のための保存されたメカニズムを示唆しています.
関連する概念動画
02:21Chromatin Packaging
Each human somatic cell contains 6 billion base-pairs of DNA. Each base-pair is 0.34 nm long, which means that each diploid cell contains a staggering 2 meters of DNA. How is such a long DNA strand packed inside a nucleus measuring only 10 - 20 microns in diameter?
The chromatin
In combination with specialized DNA binding protein called Histones, the DNA double helix forms a compact DNA: protein complex called chromatin. The chromatin itself is further compacted into higher-order structures.
The chromatin
In combination with specialized DNA binding protein called Histones, the DNA double helix forms a compact DNA: protein complex called chromatin. The chromatin itself is further compacted into higher-order structures.
01:01Euchromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions take up more dye, appearing darker, while the less-compact areas take up less dye and appear lighter. Based on the compaction level, chromatins are classified into two primary forms – euchromatin and heterochromatin.
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
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...
01:01Euchromatin
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions take up more dye, appearing darker, while the less-compact areas take up less dye and appear lighter. Based on the compaction level, chromatins are classified into two primary forms – euchromatin and heterochromatin.
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
Euchromatin is the less dense region of the chromatin and stains lighter. Euchromatin contains histone H3 extensively...
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...
01:32Chromatin Packaging
Each human somatic cell contains 6 billion base pairs of DNA. Each base pair is 0.34 nm long, meaning each diploid cell contains a staggering 2 meters of DNA. This long DNA strand is packed inside a nucleus measuring only 10-20 microns in diameter with the help of specialized DNA-binding proteins called histones. Together they form a compact DNA-protein complex called chromatin. The chromatin is further compacted into higher-order structures. The highest level of compaction is achieved during...