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RNA聚合酶I的功能架构
Claus-D Kuhn1, Sebastian R Geiger, Sonja Baumli
1Gene Center Munich and Center for Integrated Protein Science CIPSM, Department of Chemistry and Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany.
Cell
|December 28, 2007
概括
研究人员确定了酵母RNA聚合酶I (Pol I) 的结构,揭示了它如何启动核糖体生物发生. 这种结构突出了独特的子单元和细胞生长调节所必需的内在RNA分裂活动.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 核糖体生物发生对于真核细胞生长至关重要,核糖体RNA (rRNA) 通过RNA聚合酶I (Pol I) 的合成是关键的调节步骤.
- 了解Pol I的结构和功能对于破译细胞生长控制机制至关重要.
研究的目的:
- 阐明酵母RNA聚合酶I (Pol I) 功能的结构基础.
- 研究独特的Pol I子单元在转录启动和延长中的作用.
- 描述 Pol I. 的内在酶活性.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定完整的14个子单位酵母Pol I.的12 Å结构.
- 核心酶结构的同质模型.
- 对于A14/43亚复合结构的X射线晶体学.
主要成果:
- 一个混合结构的Pol I,A14/43,,和码头域揭示了一个独特的表面启动因子相互作用.
- 聚合物I的特定子单元A49和A34.5形成一个异构体,作为内在的延长因子,类似于聚合物II的TFIIF.
- 波尔I表现出内在的3'-RNA分裂活性,依赖于A12.2 C-终端域,促进rRNA校对和3'-end处理.
结论:
- 确定的结构为Pol I.对rRNA合成的调节提供了洞察力.
- 这些发现揭示了Pol I.对转录启动,延长和RNA处理的新机制.
- 这项工作促进了我们对核糖体生物生成及其在真核细胞生长中的作用的理解.
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...
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...

