Mapping Topoisomerase IV Binding and Activity Sites on the E. coli Genome
Mapping Topoisomerase IV Binding and Activity Sites on the E. coli Genome
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DOI：
10.1371/journal.pgen.1006025
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发表时间：
2016-05-01
期刊：
影响因子：
4.5
通讯作者：
Espeli, Olivier
中科院分区：
文献类型：
--
作者：
El Sayyed, Hafez;Le Chat, Ludovic;Espeli, Olivier
姐妹染色单体之间的链结连接在DNA复制过程中逐渐形成，并参与姐妹染色单体内聚的建立。Topo IV是一种细菌II型拓扑异构酶，在姐妹染色体的最终分离过程中，参与去除复制叉后面和复制后的连环链连接。我们利用基因组学和分子生物学方法研究了Topo IV在大肠杆菌中的全局dna结合和催化活性。ChIP-seq显示Topo IV与大肠杆菌染色体的相互作用受DNA复制控制。在复制过程中，Topo IV可以进入大部分基因组，但只能选择几百个特定的位点进行活动。局部染色质和基因表达环境影响位点选择。此外，在染色体二聚体分离位点dif上发现了很强的dna结合和催化活性，dif位于复制起点的对面。我们揭示了Topo IV和XerCD重组酶在不同位点的物理和功能相互作用。这种相互作用是由一种参与Ter大结构域组织的蛋白质MatP调节的。这些结果表明，Topo IV， XerCD/dif和MatP是细胞周期中染色体管理的最后一步网络的一部分。
Catenation links between sister chromatids are formed progressively during DNA replication and are involved in the establishment of sister chromatid cohesion. Topo IV is a bacterial type II topoisomerase involved in the removal of catenation links both behind replication forks and after replication during the final separation of sister chromosomes. We have investigated the global DNA-binding and catalytic activity of Topo IV in E. coli using genomic and molecular biology approaches. ChIP-seq revealed that Topo IV interaction with the E. coli chromosome is controlled by DNA replication. During replication, Topo IV has access to most of the genome but only selects a few hundred specific sites for its activity. Local chromatin and gene expression context influence site selection. Moreover strong DNA-binding and catalytic activities are found at the chromosome dimer resolution site, dif, located opposite the origin of replication. We reveal a physical and functional interaction between Topo IV and the XerCD recombinases acting at the dif site. This interaction is modulated by MatP, a protein involved in the organization of the Ter macrodomain. These results show that Topo IV, XerCD/dif and MatP are part of a network dedicated to the final step of chromosome management during the cell cycle.