関連する実験動画

Updated: Oct 9, 2025

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events

Published on: May 13, 2019

Pol IVとRDR2:二重鎖RNAを生成する二重RNAポリメラーゼ装置

Kun Huang^1,2, Xiao-Xian Wu¹, Cheng-Li Fang^1,2

¹Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.

Science (New York, N.Y.)

|December 23, 2021

まとめ

DNA依存RNAポリメラーゼIV (Pol IV) とRNA依存RNAポリメラーゼRDR2は,DNAメチル化のための小さな干渉RNA前駆体を作るのに協力する. 新しいバックトラッキング誘発RNAチャネリングメカニズムは,これらの酵素間の二重鎖RNA合成を容易にする.

科学分野:

分子生物学
エピジェネティクス
植物学

背景:

DNAメチル化は遺伝子調節とゲノム安定に不可欠です
RNAポリメラーゼIV (Pol IV) とRDR2は,植物RNA誘導DNAメチル化経路における重要な酵素である.
これらの酵素は,エピジェネティックサイレンシングに必要な小さな干渉RNA前駆体を生成します.

研究の目的:

Pol IV-RDR2ホロ酵素による二鎖RNA (dsRNA) 合成の構造的基礎を解明する.
Pol IV と RDR2 の間のRNA伝達メカニズムを理解する.
dsRNA形成におけるバックトラッキングの役割を調査する.

主な方法:

高解像度構造を決定するために,冷凍電子顕微鏡 (cryo-EM) が使用されました.
ポルIV-RDR2ホロ酵素の構造分析
逆転転写延長複合体の構造分析

主要な成果:

構造は,インターポリメラーゼチャネルを通じてPol IVとRDR2の活性部位との直接的なつながりを明らかにします.
"バックトラッキング誘発RNAチャネリング"メカニズムが特定されました.
Pol IVで生成されたトランスクリプトは,バックトラッキング後にdsRNA合成のためにRDR2に転送されます.

結論:

この研究は,植物におけるDNAメチル化に不可欠なdsRNA合成のための新しいメカニズムを明らかにしています.
この発見は,Pol IVとRDR2の機能的相互作用と調整に関する洞察を提供します.
この結果は,真核RNAポリメラーゼの進化に光を当てています.

さらに関連する動画

Chemical Triphosphorylation of Oligonucleotides

Chemical Triphosphorylation of Oligonucleotides

Published on: June 2, 2022

DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation

DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation

Published on: December 29, 2021

関連する概念動画

Eukaryotic RNA Polymerases

Eukaryotic RNA Polymerases

RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...

The Replisome

The 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...

Bacterial RNA Polymerase

Bacterial RNA Polymerase

Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...

Proofreading

Proofreading

Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template DNA strand. DNA polymerase has a higher affinity to add the correct base and ensures fidelity during DNA replication. Furthermore, it exhibits proofreading activity during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.
Errors During Replication are Corrected by the DNA Polymerase...

Transcription Initiation

Transcription Initiation

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...

Translesion DNA Polymerases

Translesion DNA Polymerases

Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...