一个Rho-依赖转录终结的异构机制
Vitaly Epshtein1, Dipak Dutta, Joseph Wade
1Department of Biochemistry, New York University School of Medicine, New York, New York 10016, USA.
Nature
|January 16, 2010
概括
细菌的Rho因子在转录的早期与RNA聚合酶结合. 这种结合触发了两步终止过程,包括无活化和解离,以控制基因表达.
科学领域:
- 细菌转录调节 细菌转录调节
- 基因表达的分子机制
- RNA与蛋白质的相互作用
背景情况:
- 罗是一种细菌RNA螺旋酶,对于转录终止至关重要.
- 罗氏与延长复合体 (EC) 相互作用的确切机制尚不清楚.
- 了解Rho的功能是控制基因表达和转录产量的关键.
研究的目的:
- 阐明Rho与细菌延长复合体 (EC) 相互作用并破坏的机制.
- 研究RNAP-Rho复合体形成在转录终止中的作用.
- 确定参与Rho依赖终止的关键步骤和分子参与者.
主要方法:
- 在整个转录周期中研究了Rho与RNA聚合酶 (RNAP) 的关联.
- 分析了Rho-依赖终结的两步过程:EC无活化和解离.
- 研究了RNAP催化中心和触发环域在终止中的作用.
主要成果:
- 在新生转录合成之前,终止致力于与RNAP关联的Rho.
- 形成RNAP-Rho复合体对于终结至关重要.
- 罗依赖终结涉及快速的EC无活化 (陷),其次是缓慢的解离.
- 电离失活是限制速度的步骤,决定了终端位置的位置.
- 触发环域调解EC无活化和解离.
结论:
- 罗依赖终结是一种由早期RNAP结合启动的两步性过程.
- 移动触发环域是Rho诱导终止的关键调解器.
- 在Rho-依赖和内在终结之间的相似性表明,在RNAPs中保留了全osteric机制.
相关概念视频
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:
Transcription Attenuation in Prokaryotes
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...
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)...
Transcriptional Regulation: Riboswitches
Riboswitches are RNA elements that regulate gene expression by altering their secondary structures in response to specific effector molecules. These elements, located in the leader regions of certain mRNAs, act as transcriptional regulators by toggling between alternative conformations to control downstream gene expression. Riboswitch-mediated regulation is a precise mechanism for modulating biosynthetic pathways, as exemplified by the riboflavin biosynthesis pathway in Bacillus...
Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
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...


