関連する実験動画
Updated: May 14, 2026

07:23
Describing a Transcription Factor Dependent Regulation of the MicroRNA Transcriptome
Published on: June 15, 2016
Maf1によるRNAポリメラーゼIII転写抑制の分子基礎
Alessandro Vannini1, Rieke Ringel, Anselm G Kusser
1Gene Center and Department of Biochemistry, Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
Cell
|October 5, 2010
まとめ
Maf1タンパク質は,ストレス下でのRNAポリメラーゼIII (Pol III) の転写開始を抑制する. 構造研究は,Maf1がPol IIIと結合し,エッセンシャルファクター募集を防止し,転写を停止することを明らかにしています.
科学分野:
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
背景:
- RNAポリメラーゼIII (Pol III) は,細胞機能に不可欠な短いRNAの転写に不可欠です.
- Maf1タンパク質は,特にストレス下では,Pol III転写の保存抑制剤である.
研究 の 目的:
- Maf1がPol IIIの転写を抑制する構造的メカニズムを解明する.
- Maf1がPol IIIとどのように相互作用し,転写開始プロセスに影響を与えるかを理解する.
主な方法:
- Maf1.1の構造を決定するためのX線結晶学.
- クリオ電子顕微鏡でPol III,活性Pol III-DNA-RNA複合体,および抑圧的なPol III-Maf1複合体を視覚化しています.
主要な成果:
- DNAとRNAの結合は,転写の開始に不可欠なPol III特異のC82/34/31サブコンプレックスの順序を誘導する.
- Maf1はPol IIIクランプに結合し,C82/34/31サブコンプレックスを再配置し,Pol IIIがプロモーターDNAとイニシアーション因子に誘導されるのを妨げます.
- Maf1結合は閉じられた複合体の形成を防ぐが,DNA-RNA・スキャフォールド結合やRNA合成を阻害しない.
結論:
- Maf1は,前始動複合体の組み立てに干渉することによって,Pol IIIの転写始動を特に抑制します.
- また,Maf1がPol IIIに結合することで,延伸期中の転写再起始を防ぐことができるとみられる.
関連する概念動画
RNA Polymerase II Accessory Proteins
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
Chromatin Structure Regulates pre-mRNA Processing
In eukaryotic cells, nascent mRNA transcripts need to undergo many post-transcriptional modifications to reach the cell cytoplasm and translate into functional proteins. For a long time, transcription and pre-mRNA processing were considered two independent events that occur sequentially in the cell. However, it has now been well established that transcription and pre-mRNA processing are two simultaneous processes that are precisely regulated inside the cell.
The chromatin structure, especially...
The chromatin structure, especially...
Master Transcription Regulators
Master transcription regulators are regulatory proteins that are predominantly responsible for regulating the expression of multiple genes. Often these genes work in concert to drive a complex process. Activation of a master transcription regulator can lead to a cascade of transcriptional activation necessary for that outcome. These regulators can directly bind to the regulatory sequences of the various genes involved, or they can indirectly regulate transcription by binding to regulatory...
Master Transcription Regulators
Master transcription regulators are regulatory proteins that are predominantly responsible for regulating the expression of multiple genes. Often these genes work in concert to drive a complex process. Activation of a master transcription regulator can lead to a cascade of transcriptional activation necessary for that outcome. These regulators can directly bind to the regulatory sequences of the various genes involved, or they can indirectly regulate transcription by binding to regulatory...
MicroRNAs
MicroRNA (miRNA) are short, regulatory RNA transcribed from introns (non-coding regions of a gene) or intergenic regions (stretches of DNA present between genes). Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself, forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA...
Regulation of Expression at Multiple Steps
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the addition of a...

