構造は,ミトコンドリア転写の段階的な開始を示している
Quinten Goovaerts1,2, Jiayu Shen3, Brent De Wijngaert1,2
1Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
Nature
|October 11, 2023
まとめ
ミトコンドリアの転写開始には,RNAポリメラーゼ (RNAP) とMtf1が含まれています. Cryo-EM構造は,RNA合成がストレスのある中間体を通して進行し,プロモーターの脱出と遺伝子発現の調節を可能にします.
科学分野:
- 分子生物学
- 構造生物学
- 遺伝子発現
背景:
- トランスクリプションの開始は遺伝子発現の重要な規制段階です.
- ミトコンドリアは,特異的な単一サブユニットRNAポリメラーゼ (RNAP) を転写に使用する.
- 以前の研究では,酵母とヒトのミトコンドリアRNAP開始複合体 (ICs) を明らかにした.
研究 の 目的:
- ミトコンドリアの転写開始の包括的,段階的なメカニズムを解明する.
- RNA合成中の酵母ミトコンドリアRNAPとMtf1の高解像度構造を決定する.
- 開始から延長への移行の構造的基盤を理解する.
主な方法:
- 高解像度冷凍電子顕微鏡 (Cryo-EM) 構造の決定
- イーストミトコンドリアRNAPとMtf1複合体の分析
- 2から8の核酸のRNA合成の特徴
主要な成果:
- 詳細な構造は,テンプレートスクランシングと非テンプレート再編成によるRNA-DNA収納を示しています.
- 早期の開始には,短時間のRNAの合成を妨害するスクランチング/アンスクランチングが含まれます.
- 階段のような非テンプレート構造はプロセス合成をサポートし,プロモーターの脱出を容易にします.
結論:
- ミトコンドリアの転写開始は,ダイナミックな構造の変化を含む細かく調整されたプロセスです.
- テンプレートスクランシングと非テンプレート再編成は,RNA合成とプロモーター脱出を調節する鍵です.
- これらの発見は,遺伝子発現の規制制御メカニズムに関する洞察を提供します.
関連する概念動画
Transcription Initiation
16.5K
Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
The promoters and enhancers and their accessory proteins allow tight regulation of...
The promoters and enhancers and their accessory proteins allow tight regulation of...
16.5K
Transcription
22.8K
Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. Additionally, many other proteins and regulatory sequences are involved in correctly synthesizing messenger RNA (mRNA). Transcriptional regulation is responsible for the differentiation of different types of cells and often for the proper cellular response to environmental signals.
Transcription Can Produce Different Kinds of RNA Molecules
In eukaryotes,...
Transcription Can Produce Different Kinds of RNA Molecules
In eukaryotes,...
22.8K
Bacterial Transcription
28.3K
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:
28.3K
Energy to Drive Translocation
2.1K
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
2.1K
Transcription Elongation Factors
10.9K
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...
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...
10.9K
Protein Transport into the Inner Mitochondrial Membrane
3.7K
Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
Transport of mitochondrial precursors across the TIM23 channel is driven by...
3.7K


