模仿基因延长的最后一步:细菌hisF基因的提示
Sara Del Duca1, Alberto Vassallo2, Giulia Semenzato3
1Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino (FI), Italy; Research Centre for Agriculture and Environment, Council for Agricultural Research and Economics (CREA-AA), Via di Lanciola 12/A, 50125 Cascine del Riccio (FI), Italy.
Gene
|June 6, 2023
概括
研究人员在实验中模拟了histidine生物合成基因hisF.F.中的基因延长. 在选择性压力下,细菌细胞迅速进化突变以恢复功能,证明了基因组的适应性.
科学领域:
- 分子进化分子进化
- 基因组学就是基因组学.
- 生物化学 生物化学
背景情况:
- 基因延长,一个涉及基因重复和分歧的过程,产生具有内部重复的蛋白质,但仍然不太了解.
- 希斯提丁生物合成基因hisA和hisF是已知基因的例子,这些基因是从较小的祖先基因通过延长形成的.
研究的目的:
- 在选择性压力下试验模仿hisF基因延长的最后阶段.
- 在模拟基因延长过程中研究细菌的突变途径和适应能力.
主要方法:
- 一个突变的Azospirillum brasilense hisF基因与一个停止编码子被引入到histidine-auxotrophic Escherichia coli.
- 转换后的大肠杆菌受到选择性压力 (低/无胺) 来分离突变菌.
- 突变的特征是,专注于停止编码子,编码子的使用,蛋白质结构和生长能力.
主要成果:
- 质量恢复取决于化时间和选择性压力强度.
- 突变主要涉及在引入的停止编码子中的单基替代,而不是回到野生类型.
- 试验保存的编码子只产生了同义替代,与停止编码子突变不同.
结论:
- 细菌细胞可以在选择性条件下快速适应其基因组,模仿诸如基因延长之类的进化事件.
- 这项研究为基因延长背后的分子机制提供了实验证据,特别是hisF基因.
- 在特定位置的突变可塑性,如停止子,有助于快速的功能恢复和潜在的进化创新.
相关概念视频
Coordination of Gene Expression Processes in Bacteria
44
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...
44
Transcription Elongation Factors
11.0K
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...
11.0K
Bacterial Transcription
28.7K
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:
28.7K
Stringent Response in E. coli
32
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
32
Replication in Prokaryotes
25.1K
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...
25.1K
Reporter Genes
11.6K
Reporter genes are a type of protein-coding gene that are often tagged to a gene of interest. Once inside a target cell, reporter genes usually produce visually identifiable characteristics like fluorescence and luminescence when expressed along with the gene of interest. Thus, reporter genes “report” the presence or absence of genes of interest in an organism, determine the gene expression pattern, or track the physical location of a DNA segment or protein in the cell.
11.6K


