A Small Regulatory RNA Contributes to the Preferential Colonization of Escherichia coli O157:H7 in the Large Intestine in Response to a Low DNA Concentration.
A Small Regulatory RNA Contributes to the Preferential Colonization of Escherichia coli O157:H7 in the Large Intestine in Response to a Low DNA Concentration.
复制标题
低 DNA 浓度下，小调节 RNA 有助于大肠杆菌 O157:H7 在大肠中优先定植
DOI：
10.3389/fmicb.2017.00274
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发表时间：
2017
影响因子：
5.2
通讯作者：
Wang L
中科院分区：
文献类型：
--
作者：
Han R;Xu L;Wang T;Liu B;Wang L
肠出血性大肠杆菌(EHEC)血清型O157：H7(O157)是人类最臭名昭著的病原体之一，在世界范围内导致严重的人类疾病。O157在通过小肠后特异性地在哺乳动物的大肠中定植，这一过程受到两个区域之间差异信号的影响。小分子调控RNA(SRNAs)能够感知和响应环境变化，调节病原菌的多种生理过程。虽然O157的一些sRNA已经被广泛研究，但这些分子是否能感觉到小肠和大肠的差异并影响O157在大肠的优先定植仍是未知的。在本研究中，我们在O157中发现了一个新的sRNA，Esr055，它感受到大肠中低浓度的DNA，并有助于该地区细菌的优先定植。O157野生型小鼠结肠粘附数是小鼠回肠粘附数的30.18倍，而ΔESR055突变体粘附数下降为回肠粘附数的13.27倍。此外，我们发现Esr055的表达直接被调节因子Deor激活，并且它的表达受到DNA的正向影响，DNA在小鼠的回肠中明显比在结肠中丰富。此外，结合信息学预测和转录分析的结果，我们发现在ΔEsr055突变体中有几个毒力基因表达上调，5个候选基因(z0568、z0974、z1356、z1926和z5187)可能是其直接靶标。
Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 (O157) is one of the most notorious human pathogens, causing severe disease in humans worldwide. O157 specifically colonizes the large intestine of mammals after passing through the small intestine, and this process is influenced by differential signals between the two regions. Small regulatory RNAs (sRNAs) are able to sense and respond to environmental changes and regulate diverse physiological processes in pathogenic bacteria. Although some sRNAs of O157 have been extensively investigated, whether these molecules can sense differences between the small and large intestine and influence the preferential colonization in the large intestine by O157 remains unknown. In this study, we identified a new sRNA, Esr055, in O157 which senses the low DNA concentration in the large intestine and contributes to the preferential colonization of the bacteria in this region. The number of O157 wild-type that adhered to the colon is 30.18 times higher than the number that adhered to the ileum of mice, while the number of the ΔEsr055 mutant that adhered to the colon decreased to 13.27 times higher than the number adhered to the ileum. Furthermore, we found that the expression of Esr055 is directly activated by the regulator, DeoR, and its expression is positively affected by DNA, which is significantly more abundant in the ileum than in the colon of mice. Additionally, combining the results of informatics predictions and transcriptomic analysis, we found that several virulence genes are up-regulated in the ΔEsr055 mutant and five candidate genes (z0568, z0974, z1356, z1926, and z5187) may be its direct targets.