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Briones AC, Lorca D, Cofre A, Cabezas CE, Krüger GI, Pardo-Esté C, Baquedano MS, Salinas CR, Espinoza M, Castro-Severyn J, Remonsellez F, Hidalgo AA, Morales EH, Saavedra CP. Genetic regulation of the ompX porin of Salmonella Typhimurium in response to hydrogen peroxide stress. Biol Res 2022; 55:8. [PMID: 35193678 PMCID: PMC8862304 DOI: 10.1186/s40659-022-00377-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/30/2022] [Indexed: 11/11/2022] Open
Abstract
Background Salmonella Typhimurium is a Gram-negative pathogen that causes a systemic disease in mice resembling typhoid fever. During its infective cycle, S. Typhimurium is phagocytized by macrophages and proliferates inside a Salmonella-containing vacuole where Salmonella is exposed and survives oxidative stress induced by H2O2 through modulation of gene expression. After exposure of Salmonella to H2O2, the expression of the porin-encoding gene ompX increases, as previously shown by microarray analysis. Expression of ompX mRNA is regulated at a post-transcriptional level by MicA and CyaR sRNAs in aerobiosis. In addition, sequence analysis predicts a site for OxyS sRNA in ompX mRNA. Results In this work we sought to evaluate the transcriptional and post-transcriptional regulation of ompX under H2O2 stress. We demonstrate that ompX expression is induced at the transcriptional level in S. Typhimurium under such conditions. Unexpectedly, an increase in ompX gene transcript and promoter activity after challenges with H2O2 does not translate into increased protein levels in the wild-type strain, suggesting that ompX mRNA is also regulated at a post-transcriptional level, at least under oxidative stress. In silico gene sequence analysis predicted that sRNAs CyaR, MicA, and OxyS could regulate ompX mRNA levels. Using rifampicin to inhibit mRNA expression, we show that the sRNAs (MicA, CyaR and OxyS) and the sRNA:mRNA chaperone Hfq positively modulate ompX mRNA levels under H2O2-induced stress in Salmonella during the exponential growth phase in Lennox broth. Conclusions Our results demonstrate that ompX mRNA is regulated in response to H2O2 by the sRNAs CyaR, MicA and OxyS is Salmonella Typhimurium. Supplementary Information The online version contains supplementary material available at 10.1186/s40659-022-00377-3.
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Affiliation(s)
- A C Briones
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - D Lorca
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - A Cofre
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - C E Cabezas
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - G I Krüger
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - C Pardo-Esté
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - M S Baquedano
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - C R Salinas
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - M Espinoza
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - J Castro-Severyn
- Laboratorio de Microbiología Aplicada Y Extremófilos, Facultad de Ingeniería Y Ciencias Geológicas, Universidad Católica 83 del Norte, Antofagasta, Chile
| | - F Remonsellez
- Laboratorio de Microbiología Aplicada Y Extremófilos, Facultad de Ingeniería Y Ciencias Geológicas, Universidad Católica 83 del Norte, Antofagasta, Chile.,Centro de Investigación Tecnológica del Agua en El Desierto (CEITSAZA), Universidad Católica del Norte, Antofagasta, Chile
| | - A A Hidalgo
- Laboratory of Molecular Pathogenesis and Antimicrobials, Escuela de Química Y Farmacia, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
| | - E H Morales
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - C P Saavedra
- Laboratorio de Microbiología Molecular, Departamento de Ciencias de La Vida, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile.
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