RNAポリメラーゼIIとAGO4に関連したタンパク質は,RNA誘導DNAメチル化で作用する
Zhihuan Gao1, Hai-Liang Liu, Lucia Daxinger
1Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA.
Nature
|April 23, 2010
まとめ
研究者らは,RNA誘導DNAメチル化 (RdDM) の新しいレギュレータであるRDM1を,アラビドプシス菌で発見した. RDM1は,植物におけるsiRNAの蓄積,DNAメチル化,および転写遺伝子の静止に不可欠である.
科学分野:
- エピジェネティクス エピジェネティクス
- 植物分子生物学 植物分子生物学
- 遺伝学 遺伝学とは
背景:
- DNAメチル化は,ユーカリ生物における重要な表遺伝的変異である.
- 植物では,24ヌクレオチド小干渉RNA (siRNAs) が,アルゴナウト4 (AGO4) とDRM2経由でDNAメチル化を誘導する.
- RNA誘導DNAメチル化 (RdDM) 経路は,遺伝子発現の調節とゲノム安定の維持に不可欠である.
研究 の 目的:
- アラビドプシス菌におけるRNA誘導DNAメチル化 (RdDM) 経路の新たな調節体を特定する.
- RdDM経路内の新たに特定されたタンパク質RDM1の機能を明らかにする.
- RDM1がsiRNAの蓄積とDNAメチレーションに影響する分子機構を理解する.
主な方法:
- アラビドプシスのRDM1機能喪失変異体の遺伝子解析.
- 小型の干渉RNA (siRNA) の蓄積の分析.
- RdDMのターゲットロケーションにおけるDNAメチル化レベルの評価.
- タンパク質の相互作用と細胞下部局所化を調査するための共免疫プレシピテーションおよび共局所化研究.
主要な成果:
- RDM1における機能喪失による変異は,24-核酸siRNAの蓄積を減少させ,DNAメチル化を低下させる.
- RDM1は,メチル化DNAと結合し,AGO4やDRM2のような主要なRdDM成分と相互作用する小さなタンパク質をコードする.
- RDM1はRNAポリメラーゼII (Pol II) と共に,核プラズマ内のRdDM標的部位に同局し,エフェクタ複合体におけるその役割を示唆する.
結論:
- RDM1は,植物RdDM経路の新しい成分であり,効率的なsiRNA生産とDNAメチル化に不可欠です.
- RDM1は,シRNA生成とDNAメチル化機構を結びつける,支架またはリンクタンパク質として作用する可能性があります.
- この研究は,RNAポリメラーゼの関与の違いを強調しており,Pol VではなくPol IIが,核プラズマの標的部位におけるRDM1を含むエフェクタ複合体と関連している.
関連する概念動画
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...
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...
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...
All three eukaryotic RNAPs require specific transcription factors, of which the...
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...
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...
The promoters and enhancers and their accessory proteins allow tight regulation of...
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...
All three eukaryotic RNAPs require specific transcription factors, of which the...
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...


