Characterization of tccP2 carried by atypical enteropathogenic Escherichia coli

Ooka, Tadasuke; Vieira, MÃ ́nica A.M.; Ogura, Yoshitoshi; Beutin, Lothar; Ragione, Roberto M. La; Diemen, Pauline M. van; Stevens, Mark P.; Aktan, Í.; Cawthraw, Shaun; Best, Angus; Hernandes, Rodrigo T.; Krause, Gladys; Gomes, Tânia A. T.; Hayashi, Tetsuya; Frankel, Gad

doi:10.1111/j.1574-6968.2007.00707.x

Cited by 23 publications

(31 citation statements)

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“…The former is represented by the tir gene of EPEC O127 : H6 strain E2348/69 (thus referred to as tir E2348/68 ) and the latter by that of EHEC O157 : H7 strain Sakai (tir Sakai ) (Ogura et al, 2007). Previous studies have shown that tir E2348/68 is widely distributed in various EPEC and EHEC lineages (Ogura et al, 2007;Ooka et al, 2007), while tir Sakai was found mainly in EHEC O157 : H7 and its close relatives O55 : H7 strains (Garmendia et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Based on the sequence variation in Tir, the protein can be classified into two subtypes (DeVinney et al, 1999): Tir Y-P, which contains a tyrosine residue (Y474 in EPEC E2348/69) that is phosphorylated by host tyrosine kinases (Kenny, 1999) and uses Nck to trigger actin polymerization (Gruenheid et al, 2001), and Tir-S, which lacks a Y474 equivalent and typically triggers actin polymerization by the TccP pathway (Garmendia et al, 2004). The former is represented by the tir gene of EPEC O127 : H6 strain E2348/69 (thus referred to as tir E2348/68 ) and the latter by that of EHEC O157 : H7 strain Sakai (tir Sakai ) (Ogura et al, 2007). Previous studies have shown that tir E2348/68 is widely distributed in various EPEC and EHEC lineages (Ogura et al, 2007;Ooka et al, 2007), while tir Sakai was found mainly in EHEC O157 : H7 and its close relatives O55 : H7 strains (Garmendia et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…However, in a recent study (Garmendia et al, 2005), a few O55 : H7 strains were found to encode Tir E2348/68 . The aim of this study was to investigate the phylogenetic relationships and genotypic differences between typical O55 : H7 strains expressing Tir Sakai , atypical O55 : H7 strains expressing Tir E2348/68 and EPEC O55 : H6 strains, which are also known to express Tir E2348/68 (Ogura et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…LEE-positive strains can be classified into several subtypes based on sequence variation within LEE genes (Blanco et al, 2006;Lacher et al, 2006;McGraw et al, 1999;Ogura et al, 2007). Variation in the eae gene, which encodes intimin, has led to classification of more than 25 intimin subtypes (Lacher et al, 2006 …”

Section: Introductionmentioning

confidence: 99%

“…EPEC and EHEC colonize the intestinal epithelia via attaching and effacing (A/E) lesions (Nataro & Kaper, 1998), which are characterized by the degeneration of the epithelial cell brush border microvilli and the formation of actin-rich pedestals within the host enterocytes beneath the adherent bacteria (Nataro & Kaper, 1998). Most of the genes required to induce A/E lesions are located on the locus of enterocyte effacement (LEE) pathogenicity island (Elliott et al, 1998;Mellies et al, 1999), which encodes the outer-membrane adhesin intimin, a type III secretion system (T3SS), transcriptional regulators, and several T3SS effector proteins including the translocated intimin receptor (Tir).LEE-positive strains can be classified into several subtypes based on sequence variation within LEE genes (Blanco et al, 2006;Lacher et al, 2006;McGraw et al, 1999;Ogura et al, 2007). Variation in the eae gene, which encodes intimin, has led to classification of more than 25 intimin subtypes (Lacher et al, 2006 …”

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Genomic comparison of the O-antigen biosynthesis gene clusters of Escherichia coli O55 strains belonging to three distinct lineages

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Typical enteropathogenic Escherichia coli (EPEC) O55 : H7 is regarded as the closest relative of enterohaemorrhagic E. coli (EHEC) O157 : H7. Both serotypes usually express the c1 intimin subclass and trigger actin polymerization by the Tir-TccP pathway. However, atypical O55 : H7 strains capable of triggering actin polymerization via the Tir-Nck pathway have recently been identified. In this study, we investigated the genotypic differences and phylogenetic relationships between typical and atypical O55 : H7 strains. We show that the atypical O55 : H7 strains, which express the h intimin subclass and lack both tccP and tccP2, belong to an E. coli lineage distinct from the typical O55 : H7 and from the EPEC O55 : H6, which also uses the Tir-Nck actin polymerization pathway. We conducted genomic comparisons of the chromosomal regions covering the O-antigen gene cluster and its flanking regions between the three O55 lineages by RFLP analysis of PCR products and DNA sequencing analysis of about 65 kb chromosomal regions. This unexpectedly revealed that horizontal transfer of large fragments (¢40 kb) encoding the O55-antigen gene cluster and part of the neighbouring colanic acid gene cluster was involved in the emergence of the three O55 E. coli lineages. The data provide new insights into the mechanisms involved in the generation of a wide variety of O-serotypes in Gram-negative bacteria. INTRODUCTIONThe O-antigen constitutes the outermost part of the LPS present in the outer membrane of Gram-negative bacteria.The chemical composition and structure of O-antigen exhibit high levels of variation even in a single species. Thus, together with flagellin (H antigen) and capsule (K antigen), O-antigen is widely used as a surface marker for serotyping of various Gram-negative bacteria. In Escherichia coli, more than 170 O-antigens have so far been identified (Scheutz et al., 2004). In general, most genes required for O-antigen biosynthesis are clustered on the E. coli chromosome between the colanic acid biosynthesis gene cluster and the histidine biosynthesis (his) operon (Reeves et al., 1996). The organization of Oantigen biosynthesis gene clusters is O-antigen-specific. Sequence comparisons in many bacterial species and strains have shown that the variation between O-antigens has been generated by horizontal transfer of a part or the entire O-antigen gene clusters (Cunneen & Reeves, 2007;Curd et al., 1998;Fegan et al., 2006;Sugiyama et al., 1998;Wang et al., 2002;Xiang et al., 1994). Thus, the serotype of a strain correlates to some extent with its phylogeny, and often provides valuable information on its pathotype.Abbreviations: A/E, attaching and effacing; CGH, comparative genomic hybridization; EAEC, enteroaggregative Escherichia coli; EAF, enteropathogenic Escherichia coli adherence factor; EHEC, enterohaemorrhagic Escherichia coli; EPEC, enteropathogenic Escherichia coli; HGT, horizontal gene transfer; IS, insertion sequence; LEE, locus of enterocyte effacement; NJ, neighbour-joining; T3SS, type III secretion system;...

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