A model for chromosome organization during the cell cycle in live E. coli.
A model for chromosome organization during the cell cycle in live E. coli.
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DOI：
10.1038/srep17133
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发表时间：
2015-11-24
影响因子：
4.6
通讯作者：
Dou S
中科院分区：
文献类型：
--
作者：
Liu Y;Xie P;Wang P;Li M;Li H;Li W;Dou S
细菌染色体 DNA 是高度紧凑的核仁。由于用于监测活细菌中 DNA 组织复杂性的方法的局限性，人们对该类核的组织知之甚少。在这里，我们报告说，通过原子力显微镜分析，环状质粒 DNA 自动包装成均匀的双环形线轴构象，以响应因急剧弯曲和解旋而产生的机械应力。利用基本物理原理推导了这一现象的机制，以解释环状DNA的自动包装行为。根据我们的观察和之前的研究，我们提出了一个关于大肠杆菌中染色体 DNA 在细胞分裂周期中如何组织的动态模型。接下来，我们通过监测细胞周期期间活大肠杆菌中 HNS 簇的发育来测试该模型。结果与模型非常一致。此外，该模型适应了迄今为止发现的体内核素的大部分显着特征。
Bacterial chromosomal DNA is a highly compact nucleoid. The organization of this nucleoid is poorly understood due to limitations in the methods used to monitor the complexities of DNA organization in live bacteria. Here, we report that circular plasmid DNA is auto-packaged into a uniform dual-toroidal-spool conformation in response to mechanical stress stemming from sharp bending and un-winding by atomic force microscopic analysis. The mechanism underlying this phenomenon was deduced with basic physical principles to explain the auto-packaging behaviour of circular DNA. Based on our observations and previous studies, we propose a dynamic model of how chromosomal DNA in E. coli may be organized during a cell division cycle. Next, we test the model by monitoring the development of HNS clusters in live E. coli during a cell cycle. The results were in close agreement with the model. Furthermore, the model accommodates a majority of the thus-far-discovered remarkable features of nucleoids in vivo.