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Involvement of PatE, a prophage-encoded AraC-like regulator, in the transcriptional activation of acid resistance pathways of enterohemorrhagic Escherichia coli strain EDL933.

ABSTRACT: Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a lethal human intestinal pathogen that causes hemorrhagic colitis and the hemolytic-uremic syndrome. EHEC is transmitted by the fecal-oral route and has a lower infectious dose than most other enteric bacterial pathogens in that fewer than 100 CFU are able to cause disease. This low infectious dose has been attributed to the ability of EHEC to survive in the acidic environment of the human stomach. In silico analysis of the genome of EHEC O157:H7 strain EDL933 revealed a gene, patE, for a putative AraC-like regulatory protein within the prophage island, CP-933H. Transcriptional analysis in E. coli showed that the expression of patE is induced during stationary phase. Data from microarray assays demonstrated that PatE activates the transcription of genes encoding proteins of acid resistance pathways. In addition, PatE downregulated the expression of a number of genes encoding heat shock proteins and the type III secretion pathway of EDL933. Transcriptional analysis and electrophoretic mobility shift assays suggested that PatE also activates the transcription of the gene for the acid stress chaperone hdeA by binding to its promoter region. Finally, assays of acid tolerance showed that increasing the expression of PatE in EHEC greatly enhanced the ability of the bacteria to survive in different acidic environments. Together, these findings indicate that EHEC strain EDL933 carries a prophage-encoded regulatory system that contributes to acid resistance.

SUBMITTER: Bender JK

PROVIDER: S-EPMC3416394 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature

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Involvement of PatE, a prophage-encoded AraC-like regulator, in the transcriptional activation of acid resistance pathways of enterohemorrhagic Escherichia coli strain EDL933.

Bender Jennifer K JK Praszkier Judyta J Wakefield Matthew J MJ Holt Kathryn K Tauschek Marija M Robins-Browne Roy M RM Yang Ji J

Applied and environmental microbiology 20120511 15

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a lethal human intestinal pathogen that causes hemorrhagic colitis and the hemolytic-uremic syndrome. EHEC is transmitted by the fecal-oral route and has a lower infectious dose than most other enteric bacterial pathogens in that fewer than 100 CFU are able to cause disease. This low infectious dose has been attributed to the ability of EHEC to survive in the acidic environment of the human stomach. In silico analysis of the genome of EHEC O15 ...[more]

PMID: 22582067

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Project description:Enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 harbors multiple prophage-associated open reading frames (ORFs) in its genome which are highly homologous to the chromosomal nanS gene. The latter is part of the nanCMS operon, which is present in most E. coli strains and encodes an esterase which is responsible for the monodeacetylation of 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac2). Whereas one prophage-borne ORF (z1466) has been characterized in previous studies, the functions of the other nanS-homologous ORFs are unknown. In the current study, the nanS-homologous ORFs of EDL933 were initially studied in silico Due to their homology to the chromosomal nanS gene and their location in prophage genomes, we designated them nanS-p and numbered the different nanS-p alleles consecutively from 1 to 10. The two alleles nanS-p2 and nanS-p4 were selected for production of recombinant proteins, their enzymatic activities were investigated, and differences in their temperature optima were found. Furthermore, a function of these enzymes in substrate utilization could be demonstrated using an E. coli C600?nanS mutant in a growth medium with Neu5,9Ac2 as the carbon source and supplementation with the different recombinant NanS-p proteins. Moreover, generation of sequential deletions of all nanS-p alleles in strain EDL933 and subsequent growth experiments demonstrated a gene dose effect on the utilization of Neu5,9Ac2 Since Neu5,9Ac2 is an important component of human and animal gut mucus and since the nutrient availability in the large intestine is limited, we hypothesize that the presence of multiple Neu5,9Ac2 esterases provides them a nutrient supply under certain conditions in the large intestine, even if particular prophages are lost.In this study, a group of homologous prophage-borne nanS-p alleles and two of the corresponding enzymes of enterohemorrhagic E. coli (EHEC) O157:H7 strain EDL933 that may be important to provide alternative genes for substrate utilization were characterized.

Dataset Information

Involvement of PatE, a prophage-encoded AraC-like regulator, in the transcriptional activation of acid resistance pathways of enterohemorrhagic Escherichia coli strain EDL933.

Publications

Involvement of PatE, a prophage-encoded AraC-like regulator, in the transcriptional activation of acid resistance pathways of enterohemorrhagic Escherichia coli strain EDL933.

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