Cabezas Carolina E, Briones Alan C, Aguirre Camila, Pardo-Esté Coral, Castro-Severyn Juan, Salinas César R, Baquedano María S, Hidalgo Alejandro A, Fuentes Juan A, Morales Eduardo H, Meneses Claudio A, Castro-Nallar Eduardo, Saavedra Claudia Paz
Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Laboratorio de Microbiología Molecular, Universidad Nacional Andrés Bello, Santiago, Chile.
Facultad de Medicina, Laboratorio de Patogénesis molecular y antimicrobianos, Universidad Nacional Andrés Bello, Santiago, Chile.
Res Microbiol. 2018 Jul-Aug;169(6):263-278. doi: 10.1016/j.resmic.2018.04.003. Epub 2018 May 29.
Salmonella Typhimurium is an intracellular pathogen that is capable of generating systemic fever in a murine model. Over the course of the infection, Salmonella faces different kinds of stressors, including harmful reactive oxygen species (ROS). Various defence mechanisms enable Salmonella to successfully complete the infective process in the presence of such stressors. The transcriptional factor SlyA is involved in the oxidative stress response and invasion of murine macrophages. We evaluated the role of SlyA in response to HO and NaOCl and found an increase of slyA expression upon exposure to these toxics. However, the SlyA target genes and the molecular mechanisms by which they influence the infective process are unknown. We hypothesised that SlyA regulates the expression of genes required for ROS resistance, metabolism, or virulence under oxidative stress conditions. Transcriptional profiling in wild type and ΔslyA strains confirmed that SlyA regulates the expression of several genes involved in virulence [sopD (STM14_3550), sopE2 (STM14_2244), hilA (STM14_3475)] and central metabolism [kgtP (STM14_3252), fruK (STM14_2722), glpA (STM14_2819)] in response to HO and NaOCl. These findings were corroborated by functional assay and transcriptional fusion assays using GFP. DNA-protein interaction assays showed that SlyA regulates these genes through direct interaction with their promoter regions.
鼠伤寒沙门氏菌是一种细胞内病原体，能够在小鼠模型中引发全身性发热。在感染过程中，沙门氏菌面临着各种应激源，包括有害的活性氧（ROS）。多种防御机制使沙门氏菌能够在这些应激源存在的情况下成功完成感染过程。转录因子SlyA参与氧化应激反应和对小鼠巨噬细胞的侵袭。我们评估了SlyA在应对过氧化氢（HO）和次氯酸钠（NaOCl）时的作用，发现暴露于这些毒物后slyA表达增加。然而，SlyA的靶基因及其影响感染过程的分子机制尚不清楚。我们假设SlyA在氧化应激条件下调节ROS抗性、代谢或毒力所需基因的表达。野生型和ΔslyA菌株的转录谱分析证实，SlyA在应对HO和NaOCl时调节多个与毒力相关基因[sopD（STM14_3550）、sopE2（STM14_2244）、hilA（STM14_3475）]和中心代谢相关基因[kgtP（STM14_3252）、fruK（STM14_2722）、glpA（STM14_2819）]的表达。使用绿色荧光蛋白（GFP）的功能测定和转录融合测定证实了这些发现。DNA-蛋白质相互作用测定表明，SlyA通过与这些基因的启动子区域直接相互作用来调节它们。
