Functional Characterization of Pseudomonas Contact Dependent Growth Inhibition (CDI) Systems.
Functional Characterization of Pseudomonas Contact Dependent Growth Inhibition (CDI) Systems.
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DOI：
10.1371/journal.pone.0147435
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Bigot S
中科院分区：
文献类型：
--
作者：
Mercy C;Ize B;Salcedo SP;de Bentzmann S;Bigot S
接触依赖抑制（CDI）毒素，传递到目标细菌细胞的细胞质，赋予宿主菌株显著的竞争优势。在细胞接触后，表面暴露的CdiA蛋白（CdiA- ct）的有毒c端区域抑制CDI-细菌的生长。CDI+细胞表达一种特异性免疫蛋白CdiI，它通过阻断同源CDI - ct的活性来防止自身抑制。CdiA-CT通过保守的肽基序与蛋白质的其余部分分开，这些肽基序分为两个不同的类别，“E”。“大肠杆菌”和“伯克氏菌型”。除假单胞菌科外，CDI系统在许多物种中都有描述。在这项研究中，我们在假单胞菌属中发现了与CDI系统相关的功能性毒素/免疫基因，这些基因通过划定多态CDI - ct结构域的肽基序的可变性而超越了传统的CDI类别。以铜绿假单胞菌PAO1为模型，我们确定了翻译抑制因子RsmA是CDI系统的负调节因子。我们的数据进一步表明，在表达条件下，铜绿假单胞菌CDI系统与粘附和生物膜形成有关，并在竞争分析中提供优势。综上所述，CDI系统可能在假单胞菌科植物的生态位适应中发挥重要作用。
Contact-dependent inhibition (CDI) toxins, delivered into the cytoplasm of target bacterial cells, confer to host strain a significant competitive advantage. Upon cell contact, the toxic C-terminal region of surface-exposed CdiA protein (CdiA-CT) inhibits the growth of CDI- bacteria. CDI+ cells express a specific immunity protein, CdiI, which protects from autoinhibition by blocking the activity of cognate CdiA-CT. CdiA-CT are separated from the rest of the protein by conserved peptide motifs falling into two distinct classes, the “E. coli”- and “Burkholderia-type”. CDI systems have been described in numerous species except in Pseudomonadaceae. In this study, we identified functional toxin/immunity genes linked to CDI systems in the Pseudomonas genus, which extend beyond the conventional CDI classes by the variability of the peptide motif that delimits the polymorphic CdiA-CT domain. Using P. aeruginosa PAO1 as a model, we identified the translational repressor RsmA as a negative regulator of CDI systems. Our data further suggest that under conditions of expression, P. aeruginosa CDI systems are implicated in adhesion and biofilm formation and provide an advantage in competition assays. All together our data imply that CDI systems could play an important role in niche adaptation of Pseudomonadaceae.