ヒストンオクタマーは,テンプレートから離れることなく,転写ポリメラーゼを回避することができます
V M Studitsky1, D J Clark, G Felsenfeld
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health Bethesda, Maryland 20892.
Cell
|January 28, 1994
まとめ
核細胞核は,転写時にDNAに沿って移動し,解離することなく,転写ポリメラーゼを回避します. この転位メカニズムは遺伝子発現の調節を保証する.
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:
- 核細胞は,真核生物のDNA包装の基本的な単位である.
- 転写中の核細胞動態を理解することは,遺伝子調節に不可欠です.
- 以前のモデルでは,ニュクレオソームの移転のための様々なメカニズムが提案されました.
研究 の 目的:
- In vitroトランスクリプション中の核細胞核の移転と再構成のメカニズムを調査する.
- 核粒子の移動におけるDNAテンプレート長と核酸濃度の役割を明らかにする.
- ヌクレオソームダイナミクスの特定のトランスロケーションモデルの証拠を提供する.
主な方法:
- SP6RNAポリメラーゼプロモーターを含む定義されたDNAテンプレート (227bpおよび262bp) に核細胞核の組み立て.
- リボヌクレオチドトリフォスファート (rNTPs) の濃度によって異なるインビトロ転写アッセイ.
- 転写後のプロモーターに対する核細胞核の位置の分析.
主要な成果:
- 転写が誘発した核細胞核の転位は75〜80 bpを超えて,プロモーターをブロックします.
- 核細胞移転は,低濃度のrNTPで分子内で行われた.
- 長いテンプレート上の核群の位置は,その初期位置に依存していた.
- データは,DNAからの解離なしにオクトーマー転送を示唆しています.
結論:
- 強力な証拠は,転写中に核細胞の再定位のためのDNA転位メカニズムをサポートしています.
- 核細胞のオクトーマーが,転写ポリメラーゼの周りを"歩いている"のです.
- このメカニズムは,核細胞体の完全性を維持しながら,転写を可能にします.
関連する概念動画
03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
02:35Transcription Elongation Factors
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
01:53Bacterial Transcription
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
02:35Transcription Elongation Factors
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
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...