Beneficial and detrimental genes in the cellular response to replication arrest.
Beneficial and detrimental genes in the cellular response to replication arrest.
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DOI：
10.1371/journal.pgen.1010564
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发表时间：
2022-12
期刊：
影响因子：
4.5
通讯作者：
中科院分区：
文献类型：
--
作者：
DNA复制对所有生物体都是必不可少的。有几个事件可以破坏复制，包括DNA损伤（例如，嘧啶二聚体，交联）和所谓的“障碍”（例如，DNA结合蛋白或转录）。细菌有几个很好的机制来修复受损的DNA，然后恢复功能复制叉。然而，在没有对DNA进行化学改变的情况下，对停滞或停滞的复制叉的修复知之甚少。利用枯草芽孢杆菌中随机转座子插入文库，我们确定了35个影响细胞生存能力的基因，这些基因暴露于抑制复制延伸的抑制剂中，但不会引起DNA的化学改变。已鉴定的基因包括参与铁硫稳态、包膜生物发生、DNA修复和重组的基因。在枯草芽孢杆菌和许多细菌中，有两种核酸酶（AddAB和RecJ）参与修复DNA化学损伤导致的复制叉的早期步骤，其中一种核酸酶的缺失会导致对DNA损伤剂的敏感性增加。这些核酸酶切除DNA末端，导致重组酶RecA组装到单链DNA上。值得注意的是，我们发现recJ的破坏增加了复制停止后细胞的存活率，这表明在DNA没有化学损伤的情况下，recJ对存活是有害的。相反，正如预期的那样，addA的破坏降低了复制停止后细胞的存活率，这表明addA促进了细胞的存活。addA和recJ突变体的不同表型似乎是由于RecA在DNA上组装的差异。RecJ似乎促进了过多的RecA细丝的组装。我们的研究结果表明，在DNA没有化学损伤的情况下，RecA对于细胞在复制停滞中存活下来是必不可少的，并且RecJ途径所支持的稳定的RecA核丝可能通过阻止对被停滞的复制叉的适当处理而导致细胞死亡。DNA复制对生命至关重要。各种各样的事件，包括DNA的化学损伤（例如，由紫外线照射引起的）和其他不会引起DNA化学修饰的细胞应激，可以扰乱和停止正在进行的复制。细胞存活通常取决于在这种中断后恢复（重新启动）复制的能力，许多生物体有多种重新启动复制的机制。许多细菌物种在DNA损伤（例如暴露于紫外线下）后有两条途径重新开始DNA复制，失去这两条途径中的任何一条都会使细胞对紫外线照射更敏感。我们发现这两种途径中的一种是有害的，而另一种途径在DNA没有化学损伤的情况下有利于细菌在复制停止后的存活。这些令人惊讶的发现突出了两种途径之间的关键差异，以及生物体在维持复制重启途径时所面临的微妙平衡，这些途径有时是有益的，有时是有害的。
DNA replication is essential for all living organisms. Several events can disrupt replication, including DNA damage (e.g., pyrimidine dimers, crosslinking) and so-called “roadblocks” (e.g., DNA-binding proteins or transcription). Bacteria have several well-characterized mechanisms for repairing damaged DNA and then restoring functional replication forks. However, little is known about the repair of stalled or arrested replication forks in the absence of chemical alterations to DNA. Using a library of random transposon insertions in Bacillus subtilis, we identified 35 genes that affect the ability of cells to survive exposure to an inhibitor that arrests replication elongation, but does not cause chemical alteration of the DNA. Genes identified include those involved in iron-sulfur homeostasis, cell envelope biogenesis, and DNA repair and recombination. In B. subtilis, and many bacteria, two nucleases (AddAB and RecJ) are involved in early steps in repairing replication forks arrested by chemical damage to DNA and loss of either nuclease causes increased sensitivity to DNA damaging agents. These nucleases resect DNA ends, leading to assembly of the recombinase RecA onto the single-stranded DNA. Notably, we found that disruption of recJ increased survival of cells following replication arrest, indicating that in the absence of chemical damage to DNA, RecJ is detrimental to survival. In contrast, and as expected, disruption of addA decreased survival of cells following replication arrest, indicating that AddA promotes survival. The different phenotypes of addA and recJ mutants appeared to be due to differences in assembly of RecA onto DNA. RecJ appeared to promote too much assembly of RecA filaments. Our results indicate that in the absence of chemical damage to DNA, RecA is dispensable for cells to survive replication arrest and that the stable RecA nucleofilaments favored by the RecJ pathway may lead to cell death by preventing proper processing of the arrested replication fork. DNA replication is essential for life. A variety of events, including chemical damage to DNA (e.g., caused by irradiation with ultraviolet light) and other cellular stresses that do not cause chemical modification of the DNA, can perturb and stop ongoing replication. Cell survival often depends on the ability to resume (restart) replication after such disruptions and many organisms have multiple mechanisms for restarting replication. Many bacterial species have two pathways for restarting DNA replication following DNA damage (e.g., exposure to ultraviolet light), and loss of either of these pathways makes cells more sensitive to UV irradiation. We found that one of these two pathways is detrimental and the other pathway is beneficial for bacterial survival following replication arrest in the absence of chemical damage to DNA. These surprising findings highlight key differences between the two pathways and the fine balance organisms face in maintaining replication restart pathways that are sometimes helpful and other times harmful.
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影响因子：
64.8
作者：
Cox, MM;Goodman, MF;Marians, KJ
通讯作者：
Marians, KJ
DOI：
10.1083/jcb.201803020
发表时间：
2018-07-02
期刊：
The Journal of cell biology
影响因子：
--
作者：
Amarh V;White MA;Leach DRF
通讯作者：
Leach DRF
影响因子：
4.5
作者：
De Septenville, Anne L.;Duigou, Stephane;Michel, Benedicte
通讯作者：
Michel, Benedicte
影响因子：
48
作者：
Gibson, Daniel G.;Young, Lei;Smith, Hamilton O.
通讯作者：
Smith, Hamilton O.
影响因子：
3.2
作者：
Goranov, Alexi I.;Kuester-Schoeck, Elke;Grossman, Alan D.
通讯作者：
Grossman, Alan D.