Transcription of the subtilase cytotoxin gene subAB1 in Shiga toxin-producing Escherichia coli is dependent on hfq and hns.

In this study, we investigated the regulation of the chromosomal subAB1 gene in laboratory E. coli strain DH5α and STEC O113:H21 strain TS18/08 using a luciferase reporter gene assay. Special emphasis was given on the role of the global regulatory protein genes hfq and hns on subAB1 promoter activity. Subsequently, quantitative real-time PCR was performed to analyze the expression of Shiga toxin 2a (Stx2a), SubAB1 and cytolethal distending toxin V (Cdt-V) genes in STEC strain TS18/08 and its isogenic hfq and hns deletion mutants. The deletion of hfq led to a significant increase of up to 2-fold in subAB1 expression, especially in the late growth phase in both strains. However, deletion of hns showed different effects on the promoter activity during the early and late exponential growth phase in both strains. Furthermore, upregulation of stx2a and cdt-V was demonstrated in hfq and hns deletion mutants in TS18/08. This data showed that the expression of subAB1 , stx2a and cdt-V is integrated in the regulatory network of global regulators Hfq and H-NS in Escherichia coli Importance: Shiga toxin-producing Escherichia coli (STEC) are responsible for outbreaks of foodborne diseases such as hemorrhagic colitis and the hemolytic uremic syndrome. The pathogenicity of those strains can be attributed among other factors to the production of toxins. Recently, the subtilase cytotoxin was detected in locus of enterocyte effacement (LEE)-negative STEC and it was confirmed that it contribut...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research