Antitoxin MqsA decreases antibiotic susceptibility through the global regulator AgtR in Pseudomonas fluorescens
Antitoxin MqsA decreases antibiotic susceptibility through the global regulator AgtR in Pseudomonas fluorescens
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DOI：
10.1128/aac.00812-23
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发表时间：
2023-10
影响因子：
4.9
通讯作者：
Siping Zhang;Yi-Ping Ye;Jun Hou;Zi-Rui Ye;Zhi-Song Wang;Xiao-Quan Yu;Ding-Ding Guo-Ding;Yong Wang-Yong-Wa
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作者：
Siping Zhang;Yi-Ping Ye;Jun Hou;Zi-Rui Ye;Zhi-Song Wang;Xiao-Quan Yu;Ding-Ding Guo-Ding;Yong Wang-Yong-Wa
摘要Ⅱ型毒素-抗毒素系统在细菌基因组中普遍存在，并在一般的应激反应中起着至关重要的作用。先前，我们证明了II型抗毒素PfMqsA通过荧光假单胞菌中的全局调节因子AgtR调节生物膜形成。在这里，我们发现PfMqsA和AgtR的C-末端DNA结合结构域都参与细菌抗生素敏感性。电泳迁移率变动分析（EMSA）显示，AgtR而不是PfMqsA与emhABC-emhR的基因间区结合，其中emhABC编码抗性-增殖-细胞分裂外排泵，emhR编码阻遏物。通过实时定量逆转录PCR和EMSA分析，我们发现AgtR通过与DNA基序[5 ′-CTAAGAAATATACTTAC-3 ′]结合直接激活emhR的表达，导致emhABC的抑制。此外，我们证明PfMqsA调节EmhABC和EmhR的表达。这些发现增强了我们对抗毒素PfMqsA导致抗生素敏感性的机制的理解。
ABSTRACT Type II toxin-antitoxin systems are highly prevalent in bacterial genomes and play crucial roles in the general stress response. Previously, we demonstrated that the type II antitoxin PfMqsA regulates biofilm formation through the global regulator AgtR in Pseudomonas fluorescens. Here, we found that both the C-terminal DNA-binding domain of PfMqsA and AgtR are involved in bacterial antibiotic susceptibility. Electrophoretic mobility shift assay (EMSA) analyses revealed that AgtR, rather than PfMqsA, binds to the intergenic region of emhABC-emhR, in which emhABC encodes an resistance-nodulation-cell division efflux pump and emhR encodes a repressor. Through quantitative real-time reverse-transcription PCR and EMSA analysis, we showed that AgtR directly activates the expression of the emhR by binding to the DNA motif [5´-CTAAGAAATATACTTAC-3´], leading to repression of the emhABC. Furthermore, we demonstrated that PfMqsA modulates the expression of EmhABC and EmhR. These findings enhance our understanding of the mechanism by which antitoxin PfMqsA contributes to antibiotic susceptibility.