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Updated: May 12, 2026

07:27
Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 30, 2010
大肠杆菌RNA聚合酶西格玛因子西格玛70在促进者-近位暂停中的功能
B Z Ring1, W S Yarnell, J W Roberts
1Section of Biochemistry, Molecular and Cell Biology Cornell University Ithaca, New York 14853, USA.
Cell
|August 9, 1996
概括
大肠杆菌RNA聚合酶中的sigma 70因子在延长过程中诱导转录暂停. 这种暂停是由特定的DNA序列介导的,并且需要西格玛70与非模板DNA链结合.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 生物化学 生物化学
背景情况:
- 西格玛70 (σ70) 是大肠杆菌RNA聚合酶的关键子单元,主要以其在转录启动中的作用而闻名.
- σ70在启动之后的精确功能,特别是在延长阶段,仍然是积极研究的领域.
研究的目的:
- 调查sigma 70在早期延长过程中诱导转录暂停中的作用.
- 为了识别参与暂停诱导的DNA信号和sigma 70区域.
- 为了阐明Sigma 70在暂停期间与DNA相互作用的机制.
主要方法:
- 对大肠杆菌RNA聚合酶中转录暂停的分析.
- 负责暂停诱导的DNA序列的识别.
- 生物化学测试以确定西格玛70区域在休息中的作用.
- 在暂停转录复合体内,西格玛70存在的特征.
主要成果:
- 西格玛70在延长的早期阶段诱导转录暂停,促进菌体兰巴达基因Q抗终结者活性.
- 一个类似于sigma 70-10促进器共识的DNA序列被确定为暂停诱导信号.
- 西格玛70的第2和第3区域足以诱导暂停.
- 西格玛70对于暂停至关重要,并且在暂停的转录复合体内保持结合.
- 暂停是由单链非模板DNA链的基因特异性识别诱导的.
结论:
- 西格玛70在转录中起着双重作用,在启动和早期延伸中起作用,以调节基因表达.
- 该机制涉及Sigma 70在转录泡中识别非模板DNA链.
- 在促进物清除后,Sigma 70很可能仍然与核心RNA聚合酶相关,并迁移到暂停部位.
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...
Transcription Elongation Factors
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 into a...
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 into a...
Bacterial Transcription
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:
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...
Transcription Elongation Factors
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 into a...
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 into a...
Transcription in Prokaryotes
Transcription is a highly regulated process that converts genetic information into RNA molecules. The transcription cycle is divided into three key stages: initiation, elongation, and termination, each driven by specific molecular mechanisms.Initiation of TranscriptionIn bacteria, transcription begins when the RNA polymerase core enzyme associates with a sigma factor to form a holoenzyme. For example, the E. coli sigma factor called σ70 forms a holoenzyme, which recognizes the -10 (Pribnow box)...

