Identification of Group A Streptococcus Genes Directly Regulated by CsrRS and Novel Intermediate Regulators.
Identification of Group A Streptococcus Genes Directly Regulated by CsrRS and Novel Intermediate Regulators.
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DOI：
10.1128/mbio.01642-21
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发表时间：
2021-08-31
期刊：
影响因子：
6.4
通讯作者：
Wessels MR
中科院分区：
文献类型：
--
作者：
Finn MB;Ramsey KM;Dove SL;Wessels MR
A组链球菌（GAS）对人类宿主的适应是由双组分系统介导的，该系统抑制外部刺激以调节细菌生理学。在这些系统中，CsrRS（也称为CovRS）是最广泛的特点，其作用是调节超过10%的GAS基因组，包括几个毒力基因。在这里，我们表明，细胞外镁和人类抗菌肽LL-37对受体激酶CsrS的反应调节剂CsrR的磷酸化具有相反的作用。与在镁或LL-37中生长相比，CsrS磷酸酶或激酶活性的遗传失活分别对CsrR磷酸化具有相似但更显著的影响。通过NanoString分析评估，CsrR磷酸化的这些变化与CsrR调节基因的抑制或激活相关。染色质免疫沉淀和DNA测序（ChIP-seq）揭示了CsrR在CsrRS调节的启动子上的占有率，以及在GAS染色体上许多其他位置的低亲和力关联。由于ChIP-seq没有检测到与一些CsrR调控基因相关的启动子处的CsrR占用，我们研究了这些基因是否可能间接受CsrR调控表达的中间调控因子控制。在CsrR调节子中的两个先前未表征的转录调节子中的任一个的表达缺陷的突变株的转录谱分析表明，一个或两个蛋白质参与了42个CsrR调节的启动子中的22个的调节，ChIP-seq检测到没有CsrR关联。两者合计，这些结果阐明CsrRS介导的GAS基因表达的调节，通过调制CsrR磷酸化，CsrR协会与受监管的启动子，和控制中间转录调节。
Adaptation of group A Streptococcus (GAS) to its human host is mediated by two-component systems that transduce external stimuli to regulate bacterial physiology. Among such systems, CsrRS (also known as CovRS) is the most extensively characterized for its role in regulating ∼10% of the GAS genome, including several virulence genes. Here, we show that extracellular magnesium and the human antimicrobial peptide LL-37 have opposing effects on the phosphorylation of the response regulator CsrR by the receptor kinase CsrS. Genetic inactivation of CsrS phosphatase or kinase activity, respectively, had similar but more pronounced effects on CsrR phosphorylation compared to growth in magnesium or LL-37. These changes in CsrR phosphorylation were correlated with the repression or activation of CsrR-regulated genes as assessed by NanoString analysis. Chromatin immunoprecipitation and DNA sequencing (ChIP-seq) revealed CsrR occupancy at CsrRS-regulated promoters and lower-affinity associations at many other locations on the GAS chromosome. Because ChIP-seq did not detect CsrR occupancy at promoters associated with some CsrR-regulated genes, we investigated whether these genes might be controlled indirectly by intermediate regulators whose expression is modulated by CsrR. Transcriptional profiling of mutant strains deficient in the expression of either of two previously uncharacterized transcription regulators in the CsrR regulon indicated that one or both proteins participated in the regulation of 22 of the 42 CsrR-regulated promoters for which no CsrR association was detected by ChIP-seq. Taken together, these results illuminate CsrRS-mediated regulation of GAS gene expression through modulation of CsrR phosphorylation, CsrR association with regulated promoters, and the control of intermediate transcription regulators.