Interlinked sister chromosomes arise in the absence of condensin during fast replication in B. subtilis.
Interlinked sister chromosomes arise in the absence of condensin during fast replication in B. subtilis.
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DOI：
10.1016/j.cub.2013.12.049
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发表时间：
2014-02-03
期刊：
影响因子：
9.2
通讯作者：
Errington, Jeff
中科院分区：
文献类型：
--
作者：
Gruber, Stephan;Veening, Jan-Willem;Bach, Juri;Blettinger, Martin;Bramkamp, Marc;Errington, Jeff
缩合蛋白是真核生物姐妹染色单体分离的关键。在大肠杆菌和枯草芽孢杆菌中，缩合素亚基的缺失导致严重的生长表型和缺乏类核的细胞的积累。然而，在许多其他细菌和缓慢生长条件下，报告的表型要温和得多或几乎不存在。这就提出了一个问题，即在不同的生长条件下，原核凝聚素在染色体分离过程中可能发挥什么作用。在B。在枯草芽孢杆菌和肺炎链球菌中，凝集素复合物通过结合到parS序列的ParB蛋白富集在单个复制起点附近的环状染色体上。使用条件等位基因的凝聚素在B. subtilis，我们表明，其活动的结果在一个立即和严重的缺陷，复制起点的分区耗尽。多个拷贝的染色体在复制起点处或附近保持不分离。令人惊讶的是，在丰富的培养基中的生长和染色体分离缺陷被抑制的复制叉速度的降低，但不是由翻译或转录的部分抑制。蛋白质凝聚素可能会阻止复制叉处姐妹DNA相互连接的形成，或促进它们在复制叉后的分解。Smc-ScpAB失活导致B. subtilis中严重的染色体分离缺陷。在缺乏原核浓缩蛋白的情况下，复制起点保持相互连接。染色体分离缺陷高度依赖于生长条件。表明在促进快速生长条件下，在B. subtilis中原核凝聚素的条件失活导致染色体分离的立即和严重缺陷。在没有Smc-ScpAB的情况下，复制起点的分离被阻断，但可以通过人工降低复制叉速度来挽救。
Condensin—an SMC-kleisin complex—is essential for efficient segregation of sister chromatids in eukaryotes. In Escherichia coli and Bacillus subtilis, deletion of condensin subunits results in severe growth phenotypes and the accumulation of cells lacking nucleoids. In many other bacteria and under slow growth conditions, however, the reported phenotypes are much milder or virtually absent. This raises the question of what role prokaryotic condensin might play during chromosome segregation under various growth conditions. In B. subtilis and Streptococcus pneumoniae, condensin complexes are enriched on the circular chromosome near the single origin of replication by ParB proteins bound to parS sequences. Using conditional alleles of condensin in B. subtilis, we demonstrate that depletion of its activity results in an immediate and severe defect in the partitioning of replication origins. Multiple copies of the chromosome remain unsegregated at or near the origin of replication. Surprisingly, the growth and chromosome segregation defects in rich medium are suppressed by a reduction of replication fork velocity but not by partial inhibition of translation or transcription. Prokaryotic condensin likely prevents the formation of sister DNA interconnections at the replication fork or promotes their resolution behind the fork. Smc-ScpAB inactivation causes a severe chromosome segregation defect in B. subtilis Replication origins remain interconnected in the absence of prokaryotic condensin Defects in chromosome segregation are highly dependent on growth conditions Reduction of replication fork velocity rescues segregation of replication origins Gruber et al. show that conditional inactivation of prokaryotic condensin in B. subtilis results in immediate and severe defects in chromosome segregation under conditions promoting fast growth. The separation of replication origins is blocked in the absence of Smc-ScpAB but can be rescued by artificial reduction of replication fork speed.
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影响因子：
16
作者：
Farcas AM;Uluocak P;Helmhart W;Nasmyth K
通讯作者：
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细胞大小和细菌中DNA复制的启动。
影响因子：
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作者：
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影响因子：
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作者：
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影响因子：
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作者：
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通讯作者：
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64.5
作者：
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