依赖RNA的RNA聚合酶II活动的分子基础
Elisabeth Lehmann1, Florian Brueckner, Patrick Cramer
1Gene Center Munich and Center for integrated Protein Science (CiPSM), Department of Chemistry and Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
Nature
|November 16, 2007
概括
RNA聚合酶II (Pol II) 表现出内在RNA依赖的RNA聚合酶 (RdRP) 活性,作为一种古老的复制酶. 这一发现表明Pol II是从RNA复制酶进化而来的,弥合了理解分子进化的差距.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 进化生物学 进化生物学
背景情况:
- RNA聚合酶II (Pol II) 主要以在转录过程中依赖DNA的RNA合成而闻名.
- 证据表明Pol II也可能具有RNA依赖RNA聚合酶 (RdRP) 活性,涉及病毒RNA复制.
研究的目的:
- 证明和描述纯化RNA聚合酶II的内在RdRP活性.
- 阐明Pol II的RdRP功能的结构和机制基础及其进化影响.
主要方法:
- 在体外测试中使用纯化的Pol II,RNA模板和核酸三酸盐.
- 用X射线晶体学来确定Pol II的结构,使用RNA模板-产品复合体.
- 研究转录因子IIS (TFIIS) 在调节RdRP活动中的作用.
主要成果:
- 波兰II通过RNA模板表现出内在的RdRP活性,活性部位与DNA依赖转录部位重叠.
- RdRP活动比依赖DNA的转录更慢,更少的过程性.
- TFIIS促进了HDV抗原体模板上的分裂和延伸,这表明它在RNA复制中发挥了作用.
结论:
- 波尔II具有固有的RdRP活性,其功能与古代RNA复制酶类似.
- 这一发现提供了一个分子联系,表明Pol II是从RNA基因组复制酶进化而来的.
- 波兰II的RdRP活性为基因表达和RNA复制机制的演变提供了洞察力.
相关概念视频
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...
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...
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...
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...
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...
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...


