まとめ
スーパーコイルドDNA
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
- バイオケミストリー バイオケミストリー
背景:
- DNAは,B型とZ型を含む,異なる螺旋状の形をとることができます.
- B-ヘリクルの形は標準的なDNA構造であり,Z-ヘリクルの形は左利きヘリックスである.
- CGリピートに富むような特定のDNA配列は,スーパーコイリングに依存して,これらの形態の間で移行することができます.
研究 の 目的:
- E. coli RNAポリメラーゼによる転写に対するDNAの螺旋構造の影響を調査する.
- CG豊富な配列のZ-DNA構成が, in vitroおよび in vivoでの転写を阻害するかどうかを決定する.
主な方法:
- (CG) 16挿入を含む超巻きプラズミッドを用いたインビトロ転写アッセイ.
- E. coli. の in vivo トランスクリプトを分析するための S1 核酸マッピング.
- CG配列のB-DNA対Z-DNA形式による転写の比較.
- コントロールとして d(CA)21 X d(TG)21 挿入物の効果をテストする.
主要な成果:
- E. coli RNAポリメラーゼは, (CG) 16配列を通して,そのB-ヘリル状の形を in vitro で転写する.
- (CG) 16配列が負のスーパーコイリングによりZ-ヘリケール形になっているとき,転写がブロックされます.
- In vivoでは,ほとんどのトランスクリプトは (CG) 16 配列を通過し,それが主に B-ヘリクルス形に存在することを示します.
- A d(CA) 21 X d(TG) 21の挿入は,同様の条件下で重要な転写阻害を引き起こさなかった.
結論:
- DNAの螺旋形は,E. coli RNAポリメラーゼによる転写に大きく影響する.
- 遺伝子内のZ-DNA形成は,強力な転写ブロックとして機能する.
- In vivoでは,細胞メカニズムは,トランスクリプションを可能にするために,CGに富んだシーケンスをB-ヘリクルス形に維持する可能性が高い.
関連する概念動画
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Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
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Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...


