Assembly of fimbrial structures in Pseudomonas aeruginosa:: Functionality and specificity of chaperone-usher machineries
Assembly of fimbrial structures in Pseudomonas aeruginosa:: Functionality and specificity of chaperone-usher machineries
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DOI：
10.1128/jb.00093-07
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发表时间：
2007-05-01
影响因子：
3.2
通讯作者：
de Bentzmann, Sophie
中科院分区：
文献类型：
--
作者：
Ruer, Segolene;Stender, Silke;de Bentzmann, Sophie
菌毛或非菌毛粘附素组装的细菌伴侣-引导途径已被证明在发病机制中发挥关键作用。这种组装机制已在具有Pap和Fim系统的致尿路感染大肠杆菌菌株中举例说明。在铜绿假单胞菌中，已在PAO 1菌株的基因组序列中鉴定出编码伴侣蛋白引导通路组分的三个基因簇（cupA、cupB和cupC）。Cup系统与Pap或Fim系统不同，因为它们明显缺乏编码菌毛亚基的基因数量。然而，已经证明CupA系统参与固体表面上的生物膜形成，而CupB和CupC系统在生物膜形成中的作用不能清楚地阐明。此外，这些基因簇被描述为在标准实验室条件下表达差。cupB和cupC簇直接受称为RocA 1/S1/R的双组分调节系统控制。在这项研究中，我们发现，CupB和CupC基因的Roc 1依赖性诱导导致高水平的生物膜形成，与CupB和CupC协同作用，在集群细菌的小菌落形成。非常重要的是，这种表型与电子显微镜观察到的细胞表面菌毛的组装有关。最后，我们观察到，CupB和CupC系统是专门在自己的菌毛亚基的组装和不可交换。
Fimbrial or nonfimbrial adhesins assembled by the bacterial chaperone-usher pathway have been demonstrated to play a key role in pathogenesis. Such an assembly mechanism has been exemplified in uropathogenic Escherichia coli strains with the Pap and the Fim systems. In Pseudomonas aeruginosa, three gene clusters (cupA, cupB, and cupC) encoding chaperone-usher pathway components have been identified in the genome sequence of the PAO1 strain. The Cup systems differ from the Pap or Fim systems, since they obviously lack numbers of genes encoding fimbrial subunits. Nevertheless, the CupA system has been demonstrated to be involved in biofilm formation on solid surfaces, whereas the role of the CupB and CupC systems in biofilm formation could not be clearly elucidated. Moreover, these gene clusters were described as poorly expressed under standard laboratory conditions. The cupB and cupC clusters are directly under the control of a two-component regulatory system designated RocA1/S1/R. In this study, we revealed that Roc1-dependent induction of the cupB and cupC genes resulted in a high level of biofilm formation, with CupB and CupC acting with synergy in clustering bacteria for microcolony formation. Very importantly, this phenotype was associated with the assembly of cell surface fimbriae visualized by electron microscopy. Finally, we observed that the CupB and CupC systems are specialized in the assembly of their own fimbrial subunits and are not exchangeable.