相关实验视频
Updated: May 17, 2026

07:44
High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
转录启动的结构基础
Yu Zhang1, Yu Feng, Sujoy Chatterjee
1Howard Hughes Medical Institute, Waksman Institute, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA.
概括
这项研究揭示了RNA聚合酶 (RNAP) 转录启动复合物的晶体结构. 这些结构详细介绍了RNAP和西格玛因子 (σ) 如何识别促进者DNA元素以启动转录.
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:
- 转录启动是基因表达的关键调节步骤.
- RNA聚合酶 (RNAP) 与促进DNA形成一个开放的复合体,以开始转录.
- 了解这个过程的结构基础是解读基因调节的关键.
研究的目的:
- 为了确定功能转录启动复合体的高分辨率晶体结构.
- 阐明RNAP,西格玛因子 (σ) 和促进DNA之间的分子相互作用.
- 为促进者识别和DNA解的机制提供见解.
主要方法:
- 采用X射线晶体学来确定结构.
- 使用了Thermus thermophilus RNA聚合酶的功能转录启动复合体, σ(A) 和促进体DNA.
- 结构的分辨率为2.9和3.0 Å分辨率.
主要成果:
- 晶体结构揭示了 σ 与 -10 元素和区分元素的特定相互作用,涉及DNA 基体脱叠和口袋插入.
- 确定了与-4/+2区域的RNAP相互作用,包括将+2基插入RNAP口袋.
- 证明 σ 和模板链单链DNA (ssDNA) 之间的相互作用预先组织了 RNAP 活性中心的 ssDNA.
结论:
- 确定的结构提供了在转录启动过程中促进体识别的详细分子视图.
- 这些发现凸显了 σ 和 RNAP 在促进体 DNA 的结合和解中所扮演的精确角色.
- 这项研究为了解转录启动复合体如何预先组织以有效地参与DNA提供了结构基础.
相关概念视频
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...
General Transcription Factors
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of hemoglobin, is present in all cells of the body. However, it is only expressed in red blood cells because the transcription factors that can bind to the promoter sequences of the beta globin gene are only expressed in these cells. Tissue-specific transcription factors also ensure that mutations in these factors may impair only the function of...
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:
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...
Eukaryotic Transcription Activators
Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These domains are...

