Inducible expression of (pp)pGpp synthetases in Staphylococcus aureus is associated with activation of stress response genes.
Inducible expression of (pp)pGpp synthetases in Staphylococcus aureus is associated with activation of stress response genes.
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DOI：
10.1371/journal.pgen.1009282
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发表时间：
2020-12
期刊：
影响因子：
4.5
通讯作者：
Wolz C
中科院分区：
文献类型：
--
作者：
Horvatek P;Salzer A;Hanna AMF;Gratani FL;Keinhörster D;Korn N;Borisova M;Mayer C;Rejman D;Mäder U;Wolz C
严格响应的特征在于信使分子pppGpp、ppGpp或pGpp（在此统称为（pp）pGpp）的合成。由（pp）pGpp积累引起的表型后果在物种之间不同，并且可以由不同的潜在机制介导。大多数全基因组分析都是在应激条件下进行的，这往往掩盖了（pp）pGpp介导的调控回路的直接影响。在金黄色葡萄球菌中，（pp）pGpp可以在氨基酸限制时经由RelA-SpoT-同系物RelSau合成，或者在细胞壁应激时经由两种小（pp）pGpp合成酶RelP或RelQ之一合成。我们使用RNA-Seq来比较响应于rel-Syn（编码RelSau的酶促区域）或relQ的合成酶的诱导的整体效应，而不需要施加额外的胁迫条件。诱导rel-Syn导致核苷酸库的变化，类似于通过tRNA合成酶抑制剂莫匹罗星诱导严格反应：GTP库减少，ATP库增加，pppGpp，ppGpp和pGpp合成。所有三种酶的诱导导致转录组的类似变化。然而，RelQ的活性低于Rel-Syn和RelP，表明其（pp）pGpp-合成活性在体内受到强烈限制。（pp）pGpp诱导导致参与蛋白质和RNA/DNA代谢的许多基因的下调。许多（pp）pGpp上调的基因是GTP敏感性CodY调节子的一部分，因此可能通过降低GTP库进行调节。检测到新的CodY非依赖性转录变化，包括参与SOS反应、铁储存（例如ftnA、dps）、氧化应激反应（例如，perR、katA、sodA）和编码细胞毒性酚可溶性调节蛋白（PSM）的psmα1-4和psm β 1 -2操纵子。对不同调控突变体中的ftnA、dps和psm基因的分析表明，它们的（pp）pGpp依赖性调控可以独立于调控因子PerR、Fur、SarA或CodY而发生。此外，psm表达与群体感应系统Agr（主要已知的psm激活剂）的表达解偶联。氧化应激反应的中心基因的表达保护细菌免受来自PSM或外源来源的预期ROS应激。因此，我们确定了一个新的联系之间的严格的反应和氧化应激在S。金黄色葡萄球菌，这可能是至关重要的生存吞噬作用。大多数细菌利用第二信使（pp）pGpp在营养限制条件下重新编程细菌代谢。在人类病原体金黄色葡萄球菌（Staphylococcus aureus）中，（pp）pGpp在毒力、吞噬体逃逸和抗生素耐受性中起重要作用。在这里，我们分析了（pp）pGpp合成的直接后果后，转录诱导的（pp）pGpp生产酶Rel，RelP或RelQ。pGpp合成引起核苷酸库的立即变化，并严重影响数百个基因的表达。S.金黄色葡萄球菌是诱导ROS诱导毒性酚可溶性调节蛋白（PSM）和同时表达解毒系统以保护生产者。这种机制可能对吞噬后的病原体有特殊的优势。
The stringent response is characterized by the synthesis of the messenger molecules pppGpp, ppGpp or pGpp (here collectively designated (pp)pGpp). The phenotypic consequences resulting from (pp)pGpp accumulation vary among species and can be mediated by different underlying mechanisms. Most genome-wide analyses have been performed under stress conditions, which often mask the immediate effects of (pp)pGpp-mediated regulatory circuits. In Staphylococcus aureus, (pp)pGpp can be synthesized via the RelA-SpoT-homolog, RelSau upon amino acid limitation or via one of the two small (pp)pGpp synthetases RelP or RelQ upon cell wall stress. We used RNA-Seq to compare the global effects in response to induction of the synthetase of rel-Syn (coding for the enzymatic region of RelSau) or relQ without the need to apply additional stress conditions. Induction of rel-Syn resulted in changes in the nucleotide pool similar to induction of the stringent response via the tRNA synthetase inhibitor mupirocin: a reduction in the GTP pool, an increase in the ATP pool and synthesis of pppGpp, ppGpp and pGpp. Induction of all three enzymes resulted in similar changes in the transcriptome. However, RelQ was less active than Rel-Syn and RelP, indicating strong restriction of its (pp)pGpp-synthesis activity in vivo. (pp)pGpp induction resulted in the downregulation of many genes involved in protein and RNA/DNA metabolism. Many of the (pp)pGpp upregulated genes are part of the GTP sensitive CodY regulon and thus likely regulated through lowering of the GTP pool. New CodY independent transcriptional changes were detected including genes involved in the SOS response, iron storage (e.g. ftnA, dps), oxidative stress response (e.g., perR, katA, sodA) and the psmα1–4 and psmß1-2 operons coding for cytotoxic, phenol soluble modulins (PSMs). Analyses of the ftnA, dps and psm genes in different regulatory mutants revealed that their (pp)pGpp-dependent regulation can occur independent of the regulators PerR, Fur, SarA or CodY. Moreover, psm expression is uncoupled from expression of the quorum sensing system Agr, the main known psm activator. The expression of central genes of the oxidative stress response protects the bacteria from anticipated ROS stress derived from PSMs or exogenous sources. Thus, we identified a new link between the stringent response and oxidative stress in S. aureus that is likely crucial for survival upon phagocytosis. Most bacteria make use of the second messenger (pp)pGpp to reprogram bacterial metabolism under nutrient-limiting conditions. In the human pathogen Staphylococcus aureus, (pp)pGpp plays an important role in virulence, phagosomal escape and antibiotic tolerance. Here, we analyzed the immediate consequences of (pp)pGpp synthesis upon transcriptional induction of the (pp)pGpp-producing enzymes Rel, RelP or RelQ. (pp)pGpp synthesis provokes immediate changes in the nucleotide pool and severely impacts the expression of hundreds of genes. A main consequence of (pp)pGpp synthesis in S. aureus is the induction of ROS-inducing toxic phenol soluble modulins (PSMs) and simultaneous expression of the detoxifying system to protect the producer. This mechanism is likely of special advantage for the pathogen after phagocytosis.
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影响因子：
4.5
作者：
Gratani FL;Horvatek P;Geiger T;Borisova M;Mayer C;Grin I;Wagner S;Steinchen W;Bange G;Velic A;Maček B;Wolz C
通讯作者：
Wolz C
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作者：
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通讯作者：
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影响因子：
6.4
作者：
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影响因子：
3.2
作者：
Grosser, Melinda R.;Weiss, Andy;Richardson, Anthony R.
通讯作者：
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影响因子：
6.4
作者：
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通讯作者：
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