E. coli Fis protein insulates the cbpA gene from uncontrolled transcription.
E. coli Fis protein insulates the cbpA gene from uncontrolled transcription.
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DOI：
10.1371/journal.pgen.1003152
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发表时间：
2013
期刊：
影响因子：
4.5
通讯作者：
Grainger DC
中科院分区：
文献类型：
--
作者：
Chintakayala K;Singh SS;Rossiter AE;Shahapure R;Dame RT;Grainger DC
大肠杆菌弯曲DNA结合蛋白A（CbpA）是一种特征性较差的类核相关因子和共伴侣。当细胞进入稳定期时，它以高水平表达。利用遗传学，生物化学和基因组学，我们已经研究了调节，和DNA结合，CbpA。我们发现，Fis，占主导地位的生长期类核蛋白，阻止CbpA在生长细胞中的表达。金融情报系统的监管涉及一种不寻常的“绝缘”机制。因此，Fis保护cbpA免受位于相邻基因中的远端启动子的影响。在稳定期，当Fis水平较低时，CbpA结合E.大肠杆菌染色体的固有弯曲的Ter宏域的偏好。cbpA基因的破坏促使DNA拓扑结构发生巨大变化。因此，我们的工作确定了Fis的新作用，并将CbpA纳入介导细菌染色体结构的因子的不断增长的网络中。染色体DNA的压缩是影响细胞生物学各个方面的基本过程。然而，我们对细菌中染色体组织的了解还很不发达。由于细菌是地球上最丰富的生物体之一，这代表了我们知识中的一个惊人空白。尽管我们缺乏了解，但人们早就知道大肠杆菌和其他细菌会在环境压力下彻底重塑染色体。这在饥饿时期最为明显，此时E. coli染色体超致密。在剖析控制这一现象的分子机制时，我们发现DNA组织蛋白之间的调节性串扰起着至关重要的作用。因此，主要的DNA折叠蛋白从生长E。大肠杆菌抑制饥饿细胞中主要染色体组织者的产生。我们的发现说明了细菌染色体的高度动态性。因此，DNA拓扑结构、基因转录和染色体折叠蛋白质相互作用，形成了一个定义染色体性质的相互作用网络。
The Escherichia coli curved DNA binding protein A (CbpA) is a poorly characterised nucleoid associated factor and co-chaperone. It is expressed at high levels as cells enter stationary phase. Using genetics, biochemistry, and genomics, we have examined regulation of, and DNA binding by, CbpA. We show that Fis, the dominant growth-phase nucleoid protein, prevents CbpA expression in growing cells. Regulation by Fis involves an unusual “insulation” mechanism. Thus, Fis protects cbpA from the effects of a distal promoter, located in an adjacent gene. In stationary phase, when Fis levels are low, CbpA binds the E. coli chromosome with a preference for the intrinsically curved Ter macrodomain. Disruption of the cbpA gene prompts dramatic changes in DNA topology. Thus, our work identifies a novel role for Fis and incorporates CbpA into the growing network of factors that mediate bacterial chromosome structure. Compaction of chromosomal DNA is a fundamental process that impacts on all aspects of cellular biology. However, our understanding of chromosome organisation in bacteria is poorly developed. Since bacteria are amongst the most abundant living organisms on the planet, this represents a startling gap in our knowledge. Despite our lack of understanding, it has long been known that Escherichia coli, and other bacteria, radically re-model their chromosomes in response to environmental stress. This is most notable during periods of starvation, when the E. coli chromosome is super compacted. In dissecting the molecular mechanisms that control this phenomenon, we have found that regulatory cross-talk between DNA–organising proteins plays an essential role. Thus, the major DNA folding protein from growing E. coli inhibits production of the major chromosome organisers in starved cells. Our findings illustrate the highly dynamic nature of bacterial chromosomes. Thus, DNA topology, gene transcription, and chromosome folding proteins entwine to create a web of interactions that define the properties of the chromosome.
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