Gu Dan, Zhang Youkun, Wang Kangru, Li Mingzhu, Jiao Xinan
Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China.
Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou, China.
Front Microbiol. 2022 Dec 22;13:1025960. doi: 10.3389/fmicb.2022.1025960. eCollection 2022.
is a foodborne pathogen that can colonize the small intestine of the host and cause diarrhea. The alternative sigma factor RpoN plays a vital role in regulating motility, carbon utilization and affects host colonization in RIMD2210633. In this study, transcriptome and phenotypic analysis further expanded our understanding of the RpoN regulon in . A deletion mutant of (Δ) was subjected to RNA-seq for systemic identification of the RpoN-controlled genes. Compared with the wild-type (WT), 399 genes were differentially expressed in the Δ strain. Moreover, 264 genes were down-regulated in the Δ strain, including those associated with nitrogen utilization (), glutamine synthetase (), formate dehydrogenase ( and -), quorum sensing ( and ), polar flagellar systems, and type VI secretion system 2 (T6SS2). Quantitative real-time reverse transcription PCR (qRT-PCR) and electrophoretic mobility shift assay (EMSA) further confirmed that RpoN could directly bind to the promoters of these genes associated with polar flagellar systems ( and ), lateral flagellar systems ( and ), T6SS2 ( and ) and glutamine synthetase (), and then positively regulate the expression of these systems. A RpoN-binding motif was identified in using the MEME suite and verified by the EMSA. Besides, the deletion of caused a significant decrease in hemolytic activity, adhesion, and cytotoxicity. Our results provide new cues to better understand the regulatory networks of RpoN protein to motility, T6SS2, and metabolism in .
是一种食源性病原体，可在宿主小肠中定殖并引起腹泻。替代σ因子RpoN在调节运动性、碳利用方面起着至关重要的作用，并影响RIMD2210633中的宿主定殖。在本研究中，转录组和表型分析进一步扩展了我们对RpoN调控子的理解。对（Δ）的缺失突变体进行RNA测序，以系统鉴定RpoN控制的基因。与野生型（WT）相比，在Δ菌株中有399个基因差异表达。此外，在Δ菌株中有264个基因下调，包括那些与氮利用（）、谷氨酰胺合成酶（）、甲酸脱氢酶（和-）、群体感应（和）、极鞭毛系统以及VI型分泌系统2（T6SS2）相关的基因。定量实时逆转录PCR（qRT-PCR）和电泳迁移率变动分析（EMSA）进一步证实，RpoN可以直接结合到与极鞭毛系统（和）、侧鞭毛系统（和）、T6SS2（和）以及谷氨酰胺合成酶（）相关的这些基因的启动子上，然后正向调节这些系统的表达。使用MEME套件在中鉴定出一个RpoN结合基序，并通过EMSA进行了验证。此外，的缺失导致溶血活性、粘附和细胞毒性显著降低。我们的结果为更好地理解RpoN蛋白对运动性、T6SS2和代谢的调控网络提供了新线索。
