Long range chromosome organization in Escherichia coli: The position of the replication origin defines the non-structured regions and the Right and Left macrodomains.
Long range chromosome organization in Escherichia coli: The position of the replication origin defines the non-structured regions and the Right and Left macrodomains.
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DOI：
10.1371/journal.pgen.1006758
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发表时间：
2017-05
期刊：
影响因子：
4.5
通讯作者：
Boccard F
中科院分区：
文献类型：
--
作者：
Duigou S;Boccard F
大肠杆菌染色体被组织成四个宏结构域（Ori、Ter、右和左）和两个非结构化区域。这种组织影响姐妹染色单体的分离、染色体DNA的移动性和染色体的细胞定位。Ter和Ori宏域的组织分别依赖于两个特定的系统，Ter域的MatP/matS和Ori域的MaoP/maoS。在这里，通过构建具有染色体重排的菌株以重排染色体片段的分布，我们揭示了非结构化区域与右侧和左侧大结构域之间的差异依赖于它们在染色体上的位置。oriC的遗传位置的变化产生的反转内的Ori宏结构域或通过插入第二oriC修改右和左宏结构域的位置，因为染色体区域最接近oriC总是非结构化的，而区域更远的行为作为宏结构域，无论其DNA序列。使用荧光显微镜，我们估计，属于一个非结构化区域的基因座显着更接近Ori MD比属于横向MD的基因座。总之，我们的研究结果表明，复制起点在大肠杆菌染色体组构中起着重要作用。大肠杆菌，因为它决定了生长细胞中宏结构域的结构和定位。染色体允许遗传信息在细胞内储存、传递和组织。在细菌中，染色体通常是圆形的，并且它们通过允许同时转录、复制和分离的几种机制来成形和组织。这些基本过程的管理方式仍不清楚，但在革兰氏阴性细菌大肠杆菌中，染色体组织的一个水平依赖于染色体在宏结构域和非结构化区域中的大规模结构化。大结构域已被定义为彼此遗传分离的兆碱基（Mb）大小的染色体结构域。E.大肠杆菌染色体分为4个宏结构域（Ter、Ori、Right和Left）和两个右/左非结构区（NSR和NSL）。组织Ter和Ori MD的因子先前已被鉴定和表征：MatP通过结合到散布在Ter MD中的23个matS序列来构建Ter MD，并且MaoP与独特序列maoS一起通过未知机制组织Ori MD。在Chaoast中，我们在这里通过重组染色体显示，右MD和左MD以及NSR和NSL区域由它们的染色体位置定义，oriC的染色体位置定义了NS区域和右/左宏结构域的位置和范围。
The Escherichia coli chromosome is organized into four macrodomains (Ori, Ter, Right and Left) and two non-structured regions. This organization influences the segregation of sister chromatids, the mobility of chromosomal DNA, and the cellular localization of the chromosome. The organization of the Ter and Ori macrodomains relies on two specific systems, MatP/matS for the Ter domain and MaoP/maoS for the Ori domain, respectively. Here by constructing strains with chromosome rearrangements to reshuffle the distribution of chromosomal segments, we reveal that the difference between the non-structured regions and the Right and Left lateral macrodomains relies on their position on the chromosome. A change in the genetic location of oriC generated either by an inversion within the Ori macrodomain or by the insertion of a second oriC modifies the position of Right and Left macrodomains, as the chromosome region the closest to oriC are always non-structured while the regions further away behave as macrodomain regardless of their DNA sequence. Using fluorescent microscopy we estimated that loci belonging to a non-structured region are significantly closer to the Ori MD than loci belonging to a lateral MD. Altogether, our results suggest that the origin of replication plays a prominent role in chromosome organization in E. coli, as it determines structuring and localization of macrodomains in growing cell. Chromosomes allow the genetic information to be stored, transmitted and organized inside the cell. In bacteria, chromosomes are generally circular and they are shaped and organized by several mechanisms allowing simultaneous transcription, replication and segregation. The way such fundamental processes are managed is still unclear, but in the Gram negative bacteria Escherichia coli, one level of chromosome organization relies on a large scale structuring of the chromosome in macrodomains and non-structured regions. Macrodomains have been defined as chromosomal domains of megabase (Mb) sized genetically isolated from each other. E. coli chromosome is divided in 4 macrodomains (Ter, Ori, Right and Left) and two right/left non-structured regions (NSR, and NSL). Factors that organize Ter and Ori MD have been identified and characterized previously: MatP structures the Ter MD by binding to 23 matS sequences disseminated in the Ter MD, and MaoP together with the unique sequence maoS organises the Ori MD by an unknown mechanism. In constrast, we show here by reshuffling the chromosome that the Right and Left MD as well as the NSR and NSL regions are defined by their chromosomal location and that the chromosomal position of oriC defines the position and the extent of the NS regions and Right/Left macrodomains.