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Role of RpoS in the Virulence of Citrobacter rodentium

机译：RpoS在啮齿动物柠檬酸杆菌毒力中的作用

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Citrobacter rodentium is a mouse enteropathogen that is closely related to Escherichia coli and causes severe colonic hyperplasia and bloody diarrhea. C. rodentium infection requires expression of genes of the locus of enterocyte effacement (LEE) pathogenicity island, which simulates infection by enteropathogenic E. coli and enterohemorrhagic E. coli in the human intestine, providing an effective model for studying enteropathogenesis. In this study we investigated the role of RpoS, the stationary phase sigma factor, in virulence in C. rodentium. Sequence analysis showed that the rpoS gene is highly conserved in C. rodentium and E. coli, exhibiting 92% identity. RpoS was critical for survival under heat shock conditions and during exposure to H2O2 and positively regulated the expression of catalase KatE (HPII). The development of the RDAR (red dry and rough) morphotype, an important virulence trait in E. coli, was also mediated by RpoS in C. rodentium. Unlike E. coli, C. rodentium grew well in the mouse colon, and the wild-type strain colonized significantly better than rpoS mutants. However, a mutation in rpoS conferred a competitive growth advantage over the wild type both in vitro in Luria-Bertani medium and in vivo in the mouse colon. Survival analysis showed that the virulence of an rpoS mutant was attenuated. The expression of genes on the LEE pathogenicity island, which are essential for colonization and virulence, was reduced in the rpoS mutant. In conclusion, RpoS is important for the stress response and is required for full virulence in C. rodentium.
机译：啮齿类柠檬酸杆菌是一种小鼠肠病原体，与大肠杆菌密切相关，可导致严重的结肠增生和血性腹泻。 C。啮齿动物感染需要表达肠上皮细胞致病性岛（LEE）致病岛的基因，该基因可模拟肠致病性 E的感染。大肠杆菌和肠出血性 E。肠中的大肠杆菌，为研究肠道发病机理提供了有效的模型。在这项研究中，我们调查了固定相sigma因子RpoS在 C毒力中的作用。啮齿动物。序列分析表明 rpoS 基因在 C中高度保守。啮齿动物和 E。大肠杆菌，具有92％的同一性。 RpoS对于在热休克条件下以及暴露于H 2 O 2 期间的存活至关重要，并正调控过氧化氢酶KatE（HPII）的表达。 RDAR（ r ed d ry a nd r ough）形态型的发展，这是一种重要的毒力性状 E。大肠杆菌，也由Rem在 C中介导。啮齿动物。与 E不同。大肠杆菌，啮齿类念珠菌在小鼠结肠中生长良好，并且野生型菌株的定殖效果明显优于 rpoS 突变体。然而，无论是在体外在Luria-Bertani培养基中还是在小鼠结肠中， rpoS 的突变都具有优于野生型的竞争性生长优势。生存分析表明， rpoS 突变体的毒力减弱。在 rpoS 突变体中，LEE致病岛上的基因表达对于定殖和毒力至关重要。总之，RpoS对于应激反应非常重要，并且对于在C中完全毒力也是必需的。啮齿动物。

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