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Transcriptional regulators of the GAD acid stress island are carried by effector protein-encoding prophages and indirectly control type III secretion in enterohemorrhagic Escherichia coli O157:H7

Tree, J.J. et al. (2011) Transcriptional regulators of the GAD acid stress island are carried by effector protein-encoding prophages and indirectly control type III secretion in enterohemorrhagic Escherichia coli O157:H7. Molecular Microbiology, 80 (5). pp. 1349-1365. ISSN 0950-382X (doi:10.1111/j.1365-2958.2011.07650.x)

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Abstract

Summary Type III secretion (T3S) plays a pivotal role in the colonization of ruminant hosts by Enterohemorrhagic Escherichia coli (EHEC). The T3S system translocates effector proteins into host cells to promote bacterial attachment and persistence. The repertoire and variation in prophage regions underpins differences in the pathogenesis and epidemiology of EHEC strains. In this study, we have used a collection of deletions in cryptic prophages and EHEC O157 O-islands to screen for novel regulators of T3S. Using this approach we have identified a family of homologous AraC-like regulators that indirectly repress T3S. These prophage-encoded secretion regulator genes (psr) are found exclusively on prophages and are associated with effector loci and the T3S activating Pch family of regulators. Transcriptional profiling, mutagenesis and DNA binding studies were used to show that these regulators usurp the conserved GAD acid stress resistance system to regulate T3S by increasing the expression of GadE (YhiE) and YhiF and that this regulation follows attachment to bovine epithelial cells. We further demonstrate that PsrA and effectors encoded within cryptic prophage CP933-N are required for persistence in a ruminant model of colonization

Item Type:Article
Status:Published
Refereed:Yes
Glasgow Author(s):Roe, Dr Andrew
Authors: Tree, J.J., Roe, A.J., Flockhart, A., McAteer, S.P., Xu, X., Shaw, D., Mahajan, A., Beatson, S.A., Best, A., Lotz, S., Woodward, M.J., La Ragione, R., Murphy, K.C., Leong, J.M., and Gally, D.L.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Molecular Microbiology
Publisher:Wiley
ISSN:0950-382X

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
491441A biochemical and molecular analysis of the YhaO membrane protein in Escherichia coli O157:H7Andrew RoeBiotechnology and Biological Sciences Research Council (BBSRC)BB/G011389/1Infection Immunity and Inflammation Life Sciences