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在E. coli B中,对一个共价连接的,分支的DNA-RNA化合物的逆转录酶依赖合成
Cell
|March 10, 1989
概括
研究人员在E. coli B中发现了一种新的分支DNA-RNA化合物,与myxobacteria不同. 一个克隆的大肠杆菌B基因段使其在大肠杆菌K12中产生,揭示了逆转录酶.
科学领域:
- 分子生物学分子生物学
- 微生物学 微生物学
- 遗传学 是一个遗传学.
背景情况:
- 分支DNA-RNA化合物以前已经在myxobacteria中被确定.
- 这些化合物表现出类似的二次结构,但在核酸序列上有所不同.
- 在大肠杆菌中这种化合物的形成和遗传基础以前是未知的.
研究的目的:
- 确定和描述E. coli B.中的一种新型分支DNA-RNA化合物.
- 为了阐明对这种化合物的形成负责的遗传决定因素.
- 研究逆转录酶在DNA-RNA化合物的生物合成中的作用.
主要方法:
- 从E. coli B.中分支DNA-RNA化合物的分离和核酸测序.
- 来自大肠杆菌B的3.5kB染色体DNA段的克隆.
- 在大肠杆菌K12中克隆部分的功能分析,包括体内和体外测试.
- 识别和测序编码DNA和RNA组件的基因以及反转录酶.
主要成果:
- 在大肠杆菌B中发现了一种新的分支DNA-RNA化合物,其序列与myxobacterial类似物不同.
- 在转移特定的3.5kB大肠杆菌BDNA片段后,在大肠杆菌K12中确认了该化合物的产生.
- 测序的DNA片段含有DNA和RNA组件的基因,以及对于化合物形成必不可少的逆转录酶.
结论:
- 在E. coli B中形成了一个独特的分支DNA-RNA化合物,这取决于特定的基因组.
- 已识别的逆转录酶在这种DNA-RNA化合物的体内和体外形成中起着至关重要的作用.
- 这一发现扩大了细菌中DNA-RNA化合物形成的已知机制.
相关概念视频
Replication in Prokaryotes
Overview
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...
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:
Restriction Enzymes
Restriction enzymes are bacterial enzymes used to cut DNA in a sequence-specific manner. To cleave DNA, they bind to specific palindromic sequences called restriction sites. Such palindromic DNA sequences or inverted repeats are commonly found in regions of functional significance, such as the origin of replication, gene operator sites, and regions containing transcription termination signals.
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
Replication in Prokaryotes
DNA replication has three main steps: initiation, elongation, and termination. Replication in prokaryotes begins when initiator proteins bind to the single origin of replication (ori) on the cell's circular chromosome. Replication then proceeds around the entire circle of the chromosome in each direction from the two replication forks, resulting in two DNA molecules.
Many Proteins Work Together to Replicate the Chromosome
Replication is coordinated and carried out by a host of specialized...
Many Proteins Work Together to Replicate the Chromosome
Replication is coordinated and carried out by a host of specialized...
Coordination of Gene Expression Processes in Bacteria
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...

