A novel toxin–antitoxin system swpAB alters gene expression patterns and reduces virulence expression in enterohemorrhagic Escherichia coli. (24th February 2023)

• Record Type: Journal Article
• Authors: Ebihara, Shinya; Yen, Hilo; Tobe, Toru
• Is Part Of: Microbiology and immunology. Volume 67:Number 4(2023)
• Page Start: 171
• Page End: 184
• Publication Date: 2023-02-24
• Subjects: EHEC -- gene expression -- pathogenicity -- RNase toxin -- TA systems; Microbiology -- Periodicals; Immunology -- Periodicals; Allergy and Immunology -- Periodicals; Microbiology -- Periodicals; Microbiologie -- Périodiques; Immunologie -- Périodiques; 579
• DOI: 10.1111/1348-0421.13054
• Languages: English
• ISSNs: 0385-5600

Abstract

Abstract: Toxin–antitoxin (TA) systems are found widely among many bacteria, including enterohemorrhagic Escherichia coli (EHEC), but their functions are still poorly understood. In this study, we identified and characterized a novel TA system belonging to the relBE family, classified as a type II TA system, found in EHEC. The protein encoded by the toxin gene is homologous to RelE ribonuclease. Using various conditions for increasing the toxin activity, high‐level induction of a toxin gene, and repression of an antitoxin gene in wild‐type EHEC, we showed that the TA system, named swpAB (switching of gene expression profile), is involved in selective repression of a set of genes, including some virulence genes, and in the reduction of adherence capacity, rather than in suppression of bacterial growth. A detailed analysis of the profiles of RNA levels along sequences at 15 min after high expression of swpA revealed that two virulence genes, espA and tir, were direct targets of the SwpA toxin. These results suggested that the swpAB system can alter gene expression patterns and change bacterial physiological activity without affecting bacterial growth.