Growth suppression by altered (p)ppGpp levels results from non-optimal resource allocation in Escherichia coli
Growth suppression by altered (p)ppGpp levels results from non-optimal resource allocation in Escherichia coli
复制标题
(p)ppGpp 水平改变导致的生长抑制是大肠杆菌中非最佳资源分配的结果
DOI：
10.1093/nar/gkz211
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发表时间：
2019-05-21
影响因子：
14.9
通讯作者：
Dai, Xiongfeng
中科院分区：
文献类型：
--
作者：
Zhu, Manlu;Dai, Xiongfeng
摘要了解细菌如何协调基因表达和生物量生长以适应各种胁迫条件仍然是生物学中的一个重大挑战。应激反应通常与细胞四磷酸或五磷酸鸟苷（p）ppGpp（也称为“魔点”）的急剧积累有关，这是参与调节细菌各种生化和生理过程的关键第二信使。尽管对（p）ppGpp在严格应答过程中的基因调控机制进行了广泛的研究，但（p）ppGpp与细菌稳态指数生长之间的联系仍然难以捉摸。在这里，我们建立了一个通用的遗传方法，通过滴定单功能（p）ppGpp合成酶或单功能（p）ppGpp水解酶，并定量表征细胞生长和基因表达，系统地干扰大肠杆菌的（p）ppGpp水平。显著地，增加和减少（p）ppGpp水平均引起E.杆菌从粗粒度的见解，我们证明，增加（p）ppGpp水平限制核糖体合成，而减少（p）ppGpp水平限制代谢蛋白质的表达，两者都导致非最佳资源分配。我们的研究揭示了（p）ppGpp通过管理全球资源分配在调节细菌生长中的深刻作用。此外，我们强调了来自果蝇的Mesh1（p）ppGpp水解酶作为询问细菌（p）ppGpp生理学的强大遗传工具。
Abstract Understanding how bacteria coordinate gene expression with biomass growth to adapt to various stress conditions remains a grand challenge in biology. Stress response is often associated with dramatic accumulation of cellular guanosine tetra- or penta-phosphate (p)ppGpp (also known as ‘magic spot’), which is a key second messenger participating in regulating various biochemical and physiological processes of bacteria. Despite of the extensive studies on the mechanism of gene regulation by (p)ppGpp during stringent response, the connection between (p)ppGpp and bacterial steady-state exponential growth remains elusive. Here, we establish a versatile genetic approach to systematically perturb the (p)ppGpp level of Escherichia coli through titrating either the single-function (p)ppGpp synthetase or the singe-function (p)ppGpp hydrolase and quantitatively characterize cell growth and gene expression. Strikingly, increased and decreased (p)ppGpp levels both cause remarkable growth suppression of E. coli. From a coarse-grained insight, we demonstrate that increased (p)ppGpp levels limit ribosome synthesis while decreased (p)ppGpp levels limit the expression of metabolic proteins, both resulting in non-optimal resource allocation. Our study reveals a profound role of (p)ppGpp in regulating bacterial growth through governing global resource allocation. Moreover, we highlight the Mesh1 (p)ppGpp hydrolase from Drosophila melanogaster as a powerful genetic tool for interrogating bacterial (p)ppGpp physiology.