静止されたクロマチンは,アクティベーター結合とPIC採用に容認性がある
1Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
Cell
|May 12, 2001
まとめ
抑制性ヘテロクロマチンは,転写因子の結合を許容するが,遺伝子活性化を阻害する. イーストの研究では,静音化タンパク質はプレイニシテーション複合体の組み立てを防ぐのではなく,ヒストンアセチル化を変化させずに下流段階を阻害することを示しています.
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
- 遺伝子規制 遺伝子規制
背景:
- 染色体構造は伝統的に,転写因子のDNAアクセシビリティの障壁として見られています.
- 遺伝子発現を調節するヘテロクロマチンの役割は複雑で,完全に理解されていません.
研究 の 目的:
- SIR生成ヘテロクロマチンが,転写因子と酵母におけるプレイニシテーション複合体の結合にどのように影響するかを調査する.
- ヘテロクロマチンが転写を抑制するメカニズムを決定する.
主な方法:
- 交配型サイレンサーに囲まれた酵母熱ショック遺伝子モデルシステムを活用しました.
- ヘテロクロマティックプロモーターの転写因子 (HSF) とプレイニシエーション複合成分 (TBP,Pol II) の占有率を分析した.
- ヘテロクロマチンの活性化中に検査されたヒストンの改変とシフト.
主要な成果:
- 抑制性ヘテロクロマチンは,HSF,TBP,Pol IIのプロモーターへの構成結合を可能にします.
- これらの要因は,静止タンパク質とデセチル化ヒストンと共存する.
- ヘテロクロマティックプロモーターはTBPとPol IIによって占められ,転写のダウンストリーム阻害を示しています.
結論:
- SIR媒介のヘテロクロマチンは,DNAアクセスを制限することではなく,プレイニシエーション複合体の募集の下流の転写を抑制します.
- ヘテロクロマチンの活性化は,ヒストンのシフトやアセチル化状態の変化なしに起こる可能性があります.
関連する概念動画
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...
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
02:42Eukaryotic Transcription Activators
Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
01:52Eukaryotic Transcription Inhibitors
Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
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...
02:04Co-activators and Co-repressors
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...