Promoter Swapping Unveils the Role of the Citrobacter rodentium CTS1 Type VI Secretion System in Interbacterial Competition
Promoter Swapping Unveils the Role of the Citrobacter rodentium CTS1 Type VI Secretion System in Interbacterial Competition
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DOI：
10.1128/aem.02504-12
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发表时间：
2013-01-01
影响因子：
4.4
通讯作者：
Cascales, Eric
中科院分区：
文献类型：
--
作者：
Gueguen, Erwan;Cascales, Eric
VI型分泌系统（T6SS）是革兰氏阴性菌中具有多种功能的多功能分泌机器，包括对真核细胞的毒力和抗菌活性。T6SS的活性可以通过培养上清中Hcp和VgrG两种蛋白的释放来跟踪。啮齿鼠柠檬酸杆菌（Citrobacter rodentium）是一种啮齿动物病原体，含有两个T6SS基因簇cts1和cts2。报告基因融合和Hcp释放实验表明CTS1 T6SS没有产生或没有活性。cts1基因座由两个不同的操纵子组成。因此，我们开发了一个新的载体，允许我们使用lambda red重组技术交换P-tac和P-BAD这两个不同的内源性启动子。人工诱导这两种启动子表明，CTS1 T6SS具有Hcp释放试验所显示的功能，并使啮齿c在与大肠杆菌的抗菌竞争实验中具有生长优势。
The type VI secretion system (T6SS) is a versatile secretion machine dedicated to various functions in Gram-negative bacteria, including virulence toward eukaryotic cells and antibacterial activity. Activity of T6SS might be followed in vitro by the release of two proteins, Hcp and VgrG, in the culture supernatant. Citrobacter rodentium, a rodent pathogen, harbors two T6SS gene clusters, cts1 and cts2. Reporter fusion and Hcp release assays suggested that the CTS1 T6SS was not produced or not active. The cts1 locus is composed of two divergent operons. We therefore developed a new vector allowing us to swap the two divergent endogenous promoters by P-tac and P-BAD using the lambda red recombination technology. Artificial induction of both promoters demonstrated that the CTS1 T6SS is functional as shown by the Hcp release assay and confers on C. rodentium a growth advantage in antibacterial competition experiments with Escherichia coli.