Increased adherence and actin pedestal formation by dam-deficient enterohaemorrhagic Escherichia coli O157:H7
Authors
Campellone, Kenneth GenoRoe, Andrew J.
Lobner-Olesen, Anders
Murphy, Kenan C.
Magoun, Loranne
Brady, Michael John
Donohue-Rolfe, Arthur
Tzipori, Saul
Gally, David L.
Leong, John M.
Marinus, Martin G.
UMass Chan Affiliations
Department of Molecular Genetics and MicrobiologyGraduate School of Biomedical Sciences
Document Type
Journal ArticlePublication Date
2007-02-17Keywords
Actins; Adhesins, Bacterial; Animals; Artificial Gene Fusion; *Bacterial Adhesion; Carrier Proteins; Disease Models, Animal; Escherichia coli Infections; Escherichia coli O157; Escherichia coli Proteins; *Gene Deletion; Gene Expression Regulation, Bacterial; Genes, Reporter; Green Fluorescent Proteins; Hela Cells; Humans; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Oligonucleotide Array Sequence Analysis; RNA, Bacterial; RNA, Messenger; Receptors, Cell Surface; Reverse Transcriptase Polymerase Chain Reaction; Site-Specific DNA-Methyltransferase; (Adenine-Specific); Swine; Transcription, GeneticLife Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
Enterohaemorrhagic Escherichia coli (EHEC) are highly infectious pathogens capable of causing severe diarrhoeal illnesses. As a critical step during their colonization, EHEC adhere intimately to intestinal epithelial cells and generate F-actin 'pedestal' structures that elevate them above surrounding cell surfaces. Intimate adhesion and pedestal formation result from delivery of the EHEC type III secretion system (TTSS) effector proteins Tir and EspF(U) into the host cell and expression of the bacterial outer membrane adhesin, intimin. To investigate a role for DNA methylation during the regulation of adhesion and pedestal formation in EHEC, we deleted the dam (DNA adenine methyltransferase) gene from EHEC O157:H7 and demonstrate that this mutation results in increased interactions with cultured host cells. EHECDeltadam exhibits dramatically elevated levels of adherence and pedestal formation when compared with wild-type EHEC, and expresses significantly higher protein levels of intimin, Tir and EspF(U). Analyses of GFP fusions, Northern blotting, reverse transcription polymerase chain reaction, and microarray experiments indicate that the abundance of Tir in the dam mutant is not due to increased transcription levels, raising the possibility that Dam methylation can indirectly control protein expression by a post-transcriptional mechanism. In contrast to other dam-deficient pathogens, EHECDeltadam is capable of robust intestinal colonization of experimentally infected animals.Source
Mol Microbiol. 2007 Mar;63(5):1468-81. Link to article on publisher's siteDOI
10.1111/j.1365-2958.2007.05602.xPermanent Link to this Item
http://hdl.handle.net/20.500.14038/33256PubMed ID
17302821Related Resources
Link to article in PubMedae974a485f413a2113503eed53cd6c53
10.1111/j.1365-2958.2007.05602.x