Defining the Rcs (Regulator of Capsule Synthesis) regulon in Enterobacteriaceae has been the major focus of several recent studies. The overall role of the Rcs system in Yersinia enterocolitica is largely unknown. Our previous study showed that RcsB inhibits motility, biofilm formation and c-di-GMP production by negatively regulating flhDC, hmsHFRS and hmsT expression. To identify other cellular functions regulated by the RcsB, gene expression profiles of the wild type and ΔrcsB mutant were compared by RNA-Seq in this study. A total of 132 differentially expressed genes regulated by the RcsB have been identified, of which 114 were upregulated and 18 were downregulated. Further, the results of RNA sequencing were discussed with a focus on the predictive roles of RcsB in the inhibition of bacterial chemotaxis, flagellar assembly and infection. To confirm these predictions, we experimentally verified that the ΔrcsB mutant activated chemotactic behavior and flagella biosynthesis, and exhibited enhanced adhesion and invasion of Y. enterocolitica to Caco-2 cells. Although RcsB largely inhibits these physiological activities, the presence of RcsB is still of great significance for optimizing the survival of Y. enterocolitica as evidenced by our previous report that RcsB confers some level of resistance to the cationic antimicrobial peptide polymyxin B in Y. enterocolitica. Overall, the information provided in this study complements our understanding of Rcs phosphorelay in the regulation of Y. enterocolitica pathogenicity, and, simultaneously, provides clues to additional roles of the Rcs system in other members of family Enterobacteriaceae.

在肠杆菌科中定义RCS（胶囊合成调节剂）调节剂已成为近期研究的重点。Rcs系统在小肠结肠炎耶尔森氏菌中的整体作用在很大程度上尚不清楚。我们以前的研究表明，RcsB通过负向调节flhDC，hmsHFRS和hmsT表达来抑制运动，生物膜形成和c-di-GMP产生。为了鉴定受RcsB调节的其他细胞功能，野生型和ΔrcsB的基因表达谱在这项研究中，通过RNA-Seq比较了突变体。总共鉴定了132个受RcsB调控的差异表达基因，其中114个被上调，而18个被下调。此外，讨论了RNA测序的结果，重点是RcsB在抑制细菌趋化性，鞭毛组装和感染中的预测作用。为了证实这些预测，我们通过实验验证了ΔrcsB突变体激活了趋化行为和鞭毛的生物合成，并表现出增强的肠炎耶尔森菌对Caco-2细胞的粘附和侵袭。尽管RcsB在很大程度上抑制了这些生理活性，但是RcsB的存在对于优化肠小肠结肠炎耶尔森氏菌的存活仍然具有重要意义。通过我们之前的报告就是一个例证是RCSB赋予抵抗一定程度的在阳离子抗菌肽多粘菌素B小肠结肠炎耶尔森菌。总体而言，本研究中提供的信息补充了我们对Rcs磷灰质在小肠结肠炎耶尔森氏菌致病性调控中的理解，同时为Rcs系统在肠杆菌科其他成员中的其他作用提供了线索。