CENP-a核細胞のセントロメア特有の組み立ては,HJURPによって媒介されます
Daniel R Foltz1, Lars E T Jansen, Aaron O Bailey
1Ludwig Institute for Cancer Research, La Jolla, CA 92093-0670, USA. dfoltz@virginia.edu
Cell
|May 5, 2009
まとめ
研究者らは,HJURPを,セントロメリッククロマチンの組み立てのための重要なヒストンチャペロンとして特定しました. このタンパク質複合体は,CENP-A (セントロメアタンパク質A) を核細胞に負荷し,細胞分裂中に正確な染色体分離を確保するために不可欠です.
科学分野:
- 細胞生物学 細胞生物学
- エピジェネティクス エピジェネティクス
- クロマチンの生物学
背景:
- セントロメアは,細胞分裂中の正確な染色体分離に不可欠です.
- 哺乳類のセントロメアには,ヒストンH3.3をCENP-Aで置き換えたエピジェネティックに特化したクロマチンが特徴です.
- CENP-Aの負荷を理解することは,セントロメア機能にとって非常に重要です.
研究 の 目的:
- CENP-Aをセントロメリックヌクレオソームにロードする特定のタンパク質を特定する.
- G1フェーズにおけるCENP-Aクロマチンアセンブリのメカニズムを解明する.
- CENP-Aの証言におけるHJURPの役割について説明します.
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特定するための測定法です.
- タンパク質の負荷のタイミングを決定するための細胞サイクル分析.
- 生化学的方法を用いたCENP-AとHJURPの相互作用の特徴化.
主要な成果:
- プレヌクレオソームCENP-AはヒストンH4,ヌクレオフォスミン1,およびHJURPと複合体を形成する.
- HJURPは,複製されたセントロメアで,新しいCENP-Aを核細胞に採用するために不可欠です.
- HJURPは,センターメアターゲティングドメイン (CATD) を介してCENP-Aを認識します.
結論:
- HJURPは,細胞サイクルを調節する,CENP-A特異的なヒストンチャペロンとして作用します.
- HJURPは,セントロメリッククロマチンの組み立てに必要です.
- このメカニズムは,適切なセントロメア形成を通じて正確な染色体分離を保証します.
関連する概念動画
02:30Histone Variants at the Centromere
Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3 variants are also...
01:12The 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...
02:10The 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.
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
02:50Spindle Assembly
Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
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...
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...