一种RNA聚合酶II和AGO4相关蛋白在RNA指导的DNA甲基化中起作用
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
概括
研究人员在Arabidopsis中发现了RDM1,它是RNA导向DNA甲基化 (RdDM) 的新调节器. 在植物中,RDM1对于siRNA积累,DNA甲基化和转录基因沉默至关重要.
科学领域:
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
- 植物分子生物学 植物分子生物学
- 遗传学 是一个遗传学.
背景情况:
- 基因甲基化是真核生物的一个关键表观遗传修饰.
- 在植物中,24核酸小干扰RNAs (siRNAs) 通过Argonaute 4 (AGO4) 和DRM2指导DNA甲基化.
- 导向RNA的DNA甲基化 (RdDM) 途径对于调节基因表达和维持基因组稳定性至关重要.
研究的目的:
- 为了确定RNA导向DNA甲基化 (RdDM) 途径的新型调节者,在Arabidopsis.
- 阐明RdDM通路内新发现的蛋白质RDM1的功能.
- 了解RDM1影响siRNA积累和DNA甲基化的分子机制.
主要方法:
- 在Arabidopsis中对RDM1功能丧失突变的遗传分析.
- 对小干扰RNA (siRNA) 积累的分析.
- 评估RdDM目标位置的DNA甲基化水平.
- 共同免疫沉和共同局部化研究,以调查蛋白质相互作用和亚细胞局部化.
主要成果:
- 在RDM1中的功能丧失突变导致24核酸siRNA积累减少和DNA甲基化减少.
- RDM1编码了一个小蛋白质,它与甲基化DNA结合,并与关键的RdDM组件 (如AGO4和DRM2) 相互作用.
- RDM1与RNA聚合酶II (Pol II) 在核等离子体中的RdDM点上同定位,这表明它在效应体复合体中的作用.
结论:
- RDM1是植物RdDM通路的新型成分,对于高效的siRNA生产和DNA甲基化至关重要.
- RDM1可能充当支架或链接蛋白,将siRNA生成与DNA甲基化机制连接起来.
- 该研究强调了RNA聚合酶参与的区别,其中Pol II而不是Pol V与核等质基位上的含有RDM1的效应体复合物有关.
相关概念视频
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...


