通过Rat1外核酶复合物的真核转录终结的结构基础
Tatsuo Yanagisawa1, Yuko Murayama1, Haruhiko Ehara1
1Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
Nature communications
|September 8, 2024
概括
在结构上表征了Rat1-Rai1-Rtt103复合体和相关的RNAPII复合体. 这些发现揭示了eukaryotic mRNA转录终止由Rat1外核酶的分子机制.
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 生化学
背景情况:
- 5'-3'外核糖酶Rat1 (也称为Xrn2) 在终止由RNA聚合酶II (RNAPII) 终止真核mRNA转录方面发挥着关键作用.
- Rat1与Rai1和Rtt103一起作为一个复合物的组成部分,作为一个"鱼雷"机制,与转录RNAPII相互作用并促进DNA/RNA解离.
研究的目的:
- 阐明Rat1-Rai1-Rtt103复合体的结构基础及其在转录终结过程中与RNAPII的相互作用.
- 为真核mRNA转录终止过程提供原子层面的见解.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定结构.
- 从酵母 Komagataella phaffii.解决了Rat1-Rai1-Rtt103复合物的结构和三个不同的Rat1-Rai1-RNAPII复合物 (类型-1,类型-1b和类型-2).
主要成果:
- Rat1-Rai1-Rtt103结构揭示了Rat1和Rai1的异构四聚体,其中Rtt103位于两个Rai1分子之间.
- 类型-1复合结构显示Rat1-Rai1异构体与RNAPIIRNA退出部位结合,将RNA提取到Rat1活性部位,代表一个"终结前"状态.
- 缺少结合DNA/RNA的1b型和2型复合体可能代表"终结后"状态.
结论:
- 确定的结构为真核mRNA转录终止机制提供了详细的说明.
- 这些发现突出了Rat1-Rai1-Rtt103复合体在参与RNAPII和促进RNA提取以终止的作用.
相关概念视频
Eukaryotic RNA Polymerases
24.0K
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...
24.0K
Transcription Attenuation in Prokaryotes
15.2K
Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure. Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
15.2K
Transcription Initiation
16.3K
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...
16.3K
Bacterial Transcription
28.1K
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
28.1K
Transcription Elongation Factors
10.8K
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA...
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA...
10.8K
Chromatin Structure Regulates pre-mRNA Processing
7.0K
In eukaryotic cells, nascent mRNA transcripts need to undergo many post-transcriptional modifications to reach the cell cytoplasm and translate into functional proteins. For a long time, transcription and pre-mRNA processing were considered two independent events that occur sequentially in the cell. However, it has now been well established that transcription and pre-mRNA processing are two simultaneous processes that are precisely regulated inside the cell.
The chromatin structure, especially...
The chromatin structure, especially...
7.0K


