Expression of the diguanylate cyclase GcbA is regulated by FleQ in response to cyclic di-GMP in Pseudomonas putida KT2440.
Expression of the diguanylate cyclase GcbA is regulated by FleQ in response to cyclic di-GMP in Pseudomonas putida KT2440.
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DOI：
10.1111/1758-2229.12478
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发表时间：
2016-12
影响因子：
3.3
通讯作者：
Yujie Xiao;Hailing Nie;Huizhong Liu;Wenli Chen;Qiaoyun Huang
中科院分区：
文献类型：
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作者：
Yujie Xiao;Hailing Nie;Huizhong Liu;Wenli Chen;Qiaoyun Huang
环二鸟苷酸（c-di-GMP）是一种普遍存在的细菌第二信使，由二鸟苷酸环化酶（DGC）合成，磷酸二酯酶（PDE）降解，调节多种细胞过程。GcbA是假单胞菌属物种中非常保守的DGC，并且已经报道影响荧光假单胞菌和铜绿假单胞菌中的生物膜形成和鞭毛运动。在这里，我们证实了GcbA在恶臭假单胞菌中的功能，并揭示了GcbA的表达是由FleQ响应于c-di-GMP而调节的。GcbA缺失损害初始生物膜的形成和提高游泳运动，但没有表现出对恶臭假单胞菌生物膜成熟的影响。c-di-GMP效应子FleQ的缺失导致gcbA转录的显著降低。此外，降低c-di-GMP水平以FleQ依赖的方式促进gcbA转录，而提高c-di-GMP水平则取消了这种促进作用。在体外实验中，我们发现FleQ与gcbA启动子DNA结合，并且该结合被c-di-GMP抑制。此外，FleQ的抗激活剂FleN和σ因子RpoN也参与gcbA的转录。我们的发现扩展了FleQ依赖性调节的复杂性，并揭示了通过FleQ调节GcbA表达的c-di-GMP的自我调节功能。
Cyclic di-GMP (c-di-GMP), a ubiquitous bacterial second messenger that regulates diverse cellular processes, is synthesized by diguanylate cyclase (DGC) and degraded by phosphodiesterase (PDE). GcbA is a well conserved DGC among Pseudomonas species, and has been reported to influence biofilm formation and flagellar motility in Pseudomonas fluorescens and Pseudomonas aeruginosa. Here we confirm the function of GcbA in Pseudomonas putida and reveal that expression of GcbA is regulated by FleQ in response to c-di-GMP. GcbA deletion impaired initial biofilm formation and enhanced swimming motility, but showed no influence on biofilm maturation in Pseudomonas putida. Deletion of the c-di-GMP effector FleQ led to a significant decrease in transcription of gcbA. Moreover, reducing c-di-GMP levels promoted gcbA transcription in a FleQ dependent way, while enhancing c-di-GMP levels abolished the promotion. In in vitro experiments we found that FleQ bound to gcbA promoter DNA and the binding was inhibited by c-di-GMP. Besides, FleN, an anti-activator of FleQ, and the sigma factor RpoN also participated in transcription of gcbA. Our finding expands the complexity of FleQ-dependent regulation and reveals a self-regulation function of c-di-GMP by regulating GcbA expression via FleQ.