The circadian clock ensures successful DNA replication in cyanobacteria.
The circadian clock ensures successful DNA replication in cyanobacteria.
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DOI：
10.1073/pnas.2022516118
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发表时间：
2021-05-18
影响因子：
11.1
通讯作者：
Rust MJ
中科院分区：
文献类型：
--
作者：
Liao Y;Rust MJ
依靠光合作用生长的蓝藻面临着根本性的挑战。基因组的复制需要几个小时，因此启动复制的决定必须在条件可能与复制完成时的未来环境状态大不相同的时候做出。我们发现，蓝藻利用它们的生物钟来确保DNA复制有效地完成，既可以在一天的早些时候安排开始，也可以通过指导代谢资源的积累来支持夜幕降临后的持续复制。当这些昼夜节律保护被移除时，复制就无法完成。这项研究将基因组复制与生物钟预测环境变化的能力联系起来。昼夜节律紊乱会导致健康和体能下降，而来自多种生物体的证据表明，生物钟紊乱与细胞周期失调有关。然而，在DNA复制的基本过程中，昼夜节律调节的功能仍然是难以捉摸的。在这里，我们证明了蓝藻长聚球菌是一种具有已知最简单的昼夜节律振荡器的模式生物，时钟在DNA复制中产生节奏，以尽量减少黄昏时必须在日落后完成的开放复制分叉的数量。生物钟产生的代谢节律确保了资源在晚上早些时候可用，以支持任何剩余的复制分叉。结合数学模型和实验，我们发现由生物钟环境失调引起的代谢缺陷会导致复制体在黑暗中过早解体和复制流产，使染色体不完整的细胞在夜间持续存在。因此，我们的研究表明，这种古老的时钟在蓝藻中的一个主要功能是确保在循环环境中成功完成基因组复制。
Cyanobacteria, which are reliant on photosynthesis for growth, face a fundamental challenge. Replicating the genome takes hours, so the decision to initiate replication must be made at time when conditions may be quite different from the future state of the environment when replication is due to complete. We found that cyanobacteria use their circadian clock to ensure that DNA replication finishes efficiently, both by scheduling initiation early in the day and by directing the accumulation of metabolic resources that support ongoing replication after nightfall. When these circadian protections are removed, replication fails to complete. This study connects genome replication to the ability of a circadian clock to anticipate environmental changes. Disruption of circadian rhythms causes decreased health and fitness, and evidence from multiple organisms links clock disruption to dysregulation of the cell cycle. However, the function of circadian regulation for the essential process of DNA replication remains elusive. Here, we demonstrate that in the cyanobacterium Synechococcus elongatus, a model organism with the simplest known circadian oscillator, the clock generates rhythms in DNA replication to minimize the number of open replication forks near dusk that would have to complete after sunset. Metabolic rhythms generated by the clock ensure that resources are available early at night to support any remaining replication forks. Combining mathematical modeling and experiments, we show that metabolic defects caused by clock–environment misalignment result in premature replisome disassembly and replicative abortion in the dark, leaving cells with incomplete chromosomes that persist through the night. Our study thus demonstrates that a major function of this ancient clock in cyanobacteria is to ensure successful completion of genome replication in a cycling environment.
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影响因子：
7.4
作者：
Green, RM;Tingay, S;Tobin, EM
通讯作者：
Tobin, EM
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：
Kiyohara, YB;Katayama, M;Kondo, T
通讯作者：
Kondo, T
DOI：
10.1073/pnas.1211144109
发表时间：
2012-08-21
影响因子：
11.1
作者：
Jain, Isha H.;Vijayan, Vikram;O'Shea, Erin K.
通讯作者：
O'Shea, Erin K.
影响因子：
56.9
作者：
Matsuo, T;Yamaguchi, S;Okamura, H
通讯作者：
Okamura, H