May 6, 2011

Transcription of the plasmid-encoded toxin gene from enteroaggregative Escherichia coli is regulated by a novel co-activation mechanism involving CRP and Fis

Molecular Microbiology
Amanda E RossiterIan R Henderson


Enteroaggregative Escherichia coli (EAEC) is a major cause of diarrhoea in developing countries. EAEC 042 is the prototypical strain. EAEC 042 secretes the functionally well-characterized Pet autotransporter toxin that contributes to virulence through its cytotoxic effects on intestinal epithelial cells. Following a global transposon mutagenesis screen of EAEC 042, the transcription factors, CRP and Fis, were identified as essential for transcription of the pet gene. Using both in vivo and in vitro techniques, we show that the pet promoter is co-dependent on CRP and Fis. We present a novel co-activation mechanism whereby CRP is placed at a non-optimal position for transcription initiation, creating dependence on Fis for full activation of pet. This study complements previous findings that establish Fis as a key virulence regulator in EAEC 042.

Mentioned in this Paper

In Vivo
Gene Expression Regulation, Bacterial
Complement System Proteins
Alkalescens-Dispar Group
Cyclic AMP Receptor Protein
Bacterial Toxins
Squamous Transitional Epithelial Cell Count

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