title: A Small Regulatory RNA Contributes to the Preferential Colonization ofEscherichia coliO157:H7 in the Large Intestine in Response to a Low DNA Concentration.
abstract: EnterohemorrhagicEscherichia 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 ΔEsr055mutant that adhered to the colon decreased to 13.27 times higher than the number adhered to the ileum. Furthermore, we found that the expression ofEsr055is 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 ΔEsr055mutant and five candidate genes (z0568, z0974, z1356, z1926, andz5187) may be its direct targets.
authors.affiliation: TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China.
authors.forename: Runhua
authors.initials: R
authors.lastname: Han
authors.affiliation: TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China.
authors.forename: Letian
authors.initials: L
authors.lastname: Xu
authors.affiliation: TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.affiliation: TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.affiliation: TEDA Institute of Biological Sciences and Biotechnology, Nankai UniversityTianjin, China; The Key Laboratory of Molecular Microbiology and Technology, Ministry of EducationTianjin, China; Tianjin Key Laboratory of Microbial Functional GenomicsTianjin, China; State Key Laboratory of Medicinal Chemical Biology, Nankai UniversityTianjin, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
keywords: DNA concentration; DeoR; O157:H7; sRNA; site-preferential colonization