Toxin-Antitoxin Systems in Escherichia coli Influence Biofilm Formation through YjgK (TabA) and Fimbriae
Toxin-Antitoxin Systems in Escherichia coli Influence Biofilm Formation through YjgK (TabA) and Fimbriae
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DOI：
10.1128/jb.01465-08
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发表时间：
2009-02-15
影响因子：
3.2
通讯作者：
Wood, Thomas K.
中科院分区：
文献类型：
--
作者：
Kim, Younghoon;Wang, Xiaoxue;Wood, Thomas K.
毒素-抗毒素(TA)系统在细菌中的作用一直存在争议。在这里，研究了五种TA系统在生物膜发育中的作用(按毒素/抗毒素分类：MazF/Maze、Rele/RelB、ChpB、YoeB/YefM和YafQ/DinJ)。尽管这多个TA系统以前被报道不会影响细菌的适合性，但我们发现，删除这五个TA系统最初(8h)减少了三个不同表面的生物膜形成，然后通过减少生物膜的扩散增加了生物膜(24h)的形成。全转录组图谱显示，5个TA系统的缺失诱导了单个基因yjgK的表达，该基因编码一个未知的蛋白；实时定量聚合酶链式反应(qRT-PCR)证实了该基因的一致诱导(在8、15和24 h)。YjgK的过表达在8h减少了生物膜的形成，在24h增加了生物膜的形成，证实了TA系统缺失后的复杂表型；YjgK基因的缺失也以预期的方式影响了生物膜的形成，在8h后增加了生物膜的形成，在24h后减少了生物膜的形成。全转录组图谱显示YjgK在8h抑制菌毛基因(qRT-PCR和酵母凝集试验证实)，这与8h取消五个TA系统后生物膜形成的减少以及YjgK过表达时的情况一致。沙柱分析证实，删除五个TA系统减少了细胞附着。此外，删除这五种毒素中的每一种都会增加8h的生物膜形成，而过表达这五种毒素会在8h抑制生物膜的形成，这与删除所有五个TA系统的结果相反，这表明涉及抗毒素的复杂调控发生了。此外，全球调节因子HHA减少生物膜形成的能力取决于这些TA系统的存在。因此，我们认为TA系统的作用之一是影响生物膜的形成。
The roles of toxin-antitoxin (TA) systems in bacteria have been debated. Here, the role of five TA systems in regard to biofilm development was investigated (listed as toxin/antitoxin: MazF/MazE, RelE/RelB, ChpB, YoeB/YefM, and YafQ/DinJ). Although these multiple TA systems were reported previously to not impact bacterial fitness, we found that deletion of the five TA systems decreased biofilm formation initially (8 h) on three different surfaces and then increased biofilm formation (24 h) by decreasing biofilm dispersal. Whole-transcriptome profiling revealed that the deletion of the five TA systems induced expression of a single gene, yjgK, which encodes an uncharacterized protein; quantitative real-time PCR (qRT-PCR) confirmed consistent induction of this gene (at 8, 15, and 24 h). Corroborating the complex phenotype seen upon deleting the TA systems, overexpression of YjgK decreased biofilm formation at 8 h and increased biofilm formation at 24 h; deletion of yjgK also affected biofilm formation in the expected manner by increasing biofilm formation after 8 h and decreasing biofilm formation after 24 h. In addition, YjgK significantly reduced biofilm dispersal. Whole-transcriptome profiling revealed YjgK represses fimbria genes at 8 h (corroborated by qRT-PCR and a yeast agglutination assay), which agrees with the decrease in biofilm formation upon deleting the five TA systems at 8 h, as well as that seen upon overexpressing YjgK. Sand column assays confirmed that deleting the five TA systems reduced cell attachment. Furthermore, deletion of each of the five toxins increased biofilm formation at 8 h, and overexpression of the five toxins repressed biofilm formation at 8 h, a result that is opposite that of deleting all five TA systems; this suggests that complex regulation occurs involving the antitoxins. Also, the ability of the global regulator Hha to reduce biofilm formation was dependent on the presence of these TA systems. Hence, we suggest that one role of TA systems is to influence biofilm formation.