Distribution of espI among clinical enterohaemorrhagic and enteropathogenic Escherichia coli isolates

Enterohaemorrhagic (EHEC) and enteropathogenic (EPEC) Escherichia coli are important diarrhoeagenic pathogens; infection is dependent on translocation of a number of type III effector proteins. Until recently all the known effectors were encoded on the LEE pathogenicity island, which also encodes the adhesin intimin and the type III secretion apparatus. Recently, a novel non-LEE effector protein, EspI/NleA, which is required for full virulence in vivo and is encoded on a prophage, was identified. The aim of this study was to determine the distribution of espI among clinical EHEC and EPEC isolates. espI was detected in 86 % and 53 % of LEE+ EHEC and EPEC strains, respectively. Moreover, the espI gene was more commonly found in patients suffering from a more severe disease.

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Characterization, Phylogeny, and Genome Analyses of Nonpathogenic Xanthomonas campestris Strains Isolated from Brassica Seeds

Phytopathology ◽

10.1094/phyto-08-19-0319-r ◽

2020 ◽

Vol 110 (5) ◽

pp. 981-988 ◽

Cited By ~ 2

Author(s):

Yung-An Lee ◽

Pei-Yu Yang ◽

Shau-Chang Huang

Keyword(s):

Type Iii Secretion ◽

Xanthomonas Campestris ◽

Pathogenicity Island ◽

Whole Genome Sequence ◽

Effector Protein ◽

Type Iii Effector ◽

Type Iii ◽

Effector Genes ◽

Genome Analyses ◽

Xanthomonas Campestris Pv Campestris

Xanthomonads were detected by using the Xan-D(CCF) medium from the brassica seeds, and their pathogenicity was determined by plant inoculation tests. It was found that some seed lots were infested with Xanthomonas campestris pv. campestris, some with X. campestris pv. raphani, and some with nonpathogenic xanthomonads. The nonpathogenic xanthomonad strains were identified as X. campestris, and the multilocus sequence analysis showed that the nonpathogenic X. campestris strains were grouped together with pathogenic X. campestris, but not with nonpathogenic strains of X. arboricola. In addition, all isolated X. campestris pv. campestris and X. campestris pv. raphani strains were positive in the hrpF-PCR, but the nonpathogenic strains were negative. It was further found that nonpathogenic X. campestris strain nE1 does not contain the entire pathogenicity island (hrp gene cluster; type III secretion system) and all type III effector protein genes based on the whole genome sequence analyses. The nonpathogenic X. campestris strain nE1 could acquire the entire pathogenicity island from the endemic X. campestris pv. campestris and X. campestris pv. raphani strains by conjugation, but type III effector genes were not cotransferred. The studies showed that the nonpathogenic X. campestris strains indeed exist on the brassica seeds, but it could be differentiated by the PCR assays on the hrp and type III effector genes. Nevertheless, the nonpathogenic X. campestris strains cannot be ignored because they may be potential gene resources to increase genetic diversity in the endemic pathogenic X. campestris pv. campestris and X. campestris pv. raphani strains.

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A Degenerate Type III Secretion System from Septicemic Escherichia coli Contributes to Pathogenesis

Journal of Bacteriology ◽

10.1128/jb.187.23.8164-8171.2005 ◽

2005 ◽

Vol 187 (23) ◽

pp. 8164-8171 ◽

Cited By ~ 44

Author(s):

Diana Ideses ◽

Uri Gophna ◽

Yossi Paitan ◽

Roy R. Chaudhuri ◽

Mark J. Pallen ◽

...

Keyword(s):

Escherichia Coli ◽

Gene Cluster ◽

Type Iii Secretion ◽

Type Iii Secretion System ◽

Gene Clusters ◽

Secretion System ◽

Effector Proteins ◽

E Coli ◽

Type Iii

ABSTRACT The type III secretion system (T3SS) is an important virulence factor used by several gram-negative bacteria to deliver effector proteins which subvert host cellular processes. Enterohemorrhagic Escherichia coli O157 has a well-defined T3SS involved in attachment and effacement (ETT1) and critical for virulence. A gene cluster potentially encoding an additional T3SS (ETT2), which resembles the SPI-1 system in Salmonella enterica, was found in its genome sequence. The ETT2 gene cluster has since been found in many E. coli strains, but its in vivo role is not known. Many of the ETT2 gene clusters carry mutations and deletions, raising the possibility that they are not functional. Here we show the existence in septicemic E. coli strains of an ETT2 gene cluster, ETT2sepsis, which, although degenerate, contributes to pathogenesis. ETT2sepsis has several premature stop codons and a large (5 kb) deletion, which is conserved in 11 E. coli strains from cases of septicemia and newborn meningitis. A null mutant constructed to remove genes coding for the putative inner membrane ring of the secretion complex exhibited significantly reduced virulence. These results are the first demonstration of the importance of ETT2 for pathogenesis.

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Role of the Salmonella Pathogenicity Island 1 (SPI-1) Protein InvB in Type III Secretion of SopE and SopE2, Two Salmonella Effector Proteins Encoded Outside of SPI-1

Journal of Bacteriology ◽

10.1128/jb.185.23.6950-6967.2003 ◽

2003 ◽

Vol 185 (23) ◽

pp. 6950-6967 ◽

Cited By ~ 62

Author(s):

Kristin Ehrbar ◽

Andrea Friebel ◽

Samuel I. Miller ◽

Wolf-Dietrich Hardt

Keyword(s):

Type Iii Secretion ◽

Inflammatory Responses ◽

Pathogenicity Island ◽

Effector Proteins ◽

Host Cells ◽

Effector Protein ◽

Dependent Manner ◽

Type Iii ◽

Serovar Typhimurium

ABSTRACT Salmonella enterica subspecies 1 serovar Typhimurium encodes a type III secretion system (TTSS) within Salmonella pathogenicity island 1 (SPI-1). This TTSS injects effector proteins into host cells to trigger invasion and inflammatory responses. Effector proteins are recognized by the TTSS via signals encoded in their N termini. Specific chaperones can be involved in this process. The chaperones InvB, SicA, and SicP are encoded in SPI-1 and are required for transport of SPI-1-encoded effectors. Several key effector proteins, like SopE and SopE2, are located outside of SPI-1 but are secreted in an SPI-1-dependent manner. It has not been clear how these effector proteins are recognized by the SPI-1 TTSS. Using pull-down and coimmunoprecipitation assays, we found that SopE is copurified with InvB, the known chaperone for the SPI-1-encoded effector protein Sip/SspA. We also found that InvB is required for secretion and translocation of SopE and SopE2 and for stabilization of SopE2 in the bacterial cytosol. Our data demonstrate that effector proteins encoded within and outside of SPI-1 use the same chaperone for secretion via the SPI-1 TTSS.

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SseA is a chaperone for the SseB and SseD translocon components of the Salmonella pathogenicity-island-2-encoded type III secretion system

Microbiology ◽

10.1099/mic.0.26190-0 ◽

2003 ◽

Vol 149 (5) ◽

pp. 1103-1111 ◽

Cited By ~ 30

Author(s):

Javier Ruiz-Albert ◽

Rosanna Mundy ◽

Xiu-Jun Yu ◽

Carmen R. Beuzón ◽

David W. Holden

Keyword(s):

Type Iii Secretion ◽

Sequence Similarity ◽

Coiled Coil ◽

Type Iii Secretion System ◽

Pathogenicity Island ◽

Secretion System ◽

Effector Proteins ◽

Type Iii ◽

Virulence Attenuation

The type III secretion system (TTSS) encoded by the Salmonella pathogenicity island 2 (SPI-2) is required for bacterial replication inside macrophages and for systemic infection in mice. Many TTSS secreted proteins, including effectors and components of the translocon, require chaperones which promote their stability, prevent their premature interactions or facilitate their secretion. In this study, the function of the first gene (sseA) of one of the SPI-2 operons (sseA–G) was investigated. This operon includes genes that encode translocon components (SseB, SseC and SseD), translocated proteins (SseF and SseG) and putative chaperones (SscA and SscB). sseA encodes a 12·5 kDa protein with a C-terminal region with the potential to form a coiled-coil structure, but no sequence similarity to other proteins. Mutation of sseA results in severe virulence attenuation and an intracellular replication defect. It is shown here that SseA is not a secreted protein, but is required for SPI-2-dependent translocation of two effector proteins (SifA and PipB). Furthermore, the translocon components SseB and SseD were not detected in an sseA mutant strain. By using a yeast two-hybrid assay and column binding experiments, it is demonstrated that SseA interacts directly with SseB and SseD. These results indicate that SseA is a chaperone for SseB and SseD. The inability of an sseA mutant to assemble the SPI-2 TTSS translocon accounts for its high level of virulence attenuation in vivo. To the authors' knowledge, this is the first chaperone described for the SPI-2 TTSS.

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An inducible lambdoid prophage encoding cytolethal distending toxin (Cdt-I) and a type III effector protein in enteropathogenic Escherichia coli

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0706695104 ◽

2007 ◽

Vol 104 (36) ◽

pp. 14483-14488 ◽

Cited By ~ 37

Author(s):

M. Asakura ◽

A. Hinenoya ◽

M. S. Alam ◽

K. Shima ◽

S. H. Zahid ◽

...

Keyword(s):

Escherichia Coli ◽

Effector Protein ◽

Cytolethal Distending Toxin ◽

Enteropathogenic Escherichia Coli ◽

Type Iii Effector ◽

Type Iii ◽

Lambdoid Prophage

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CesD2 of Enteropathogenic Escherichia coli Is a Second Chaperone for the Type III Secretion Translocator Protein EspD

Infection and Immunity ◽

10.1128/iai.71.4.2130-2141.2003 ◽

2003 ◽

Vol 71 (4) ◽

pp. 2130-2141 ◽

Cited By ~ 35

Author(s):

Bianca C. Neves ◽

Rosanna Mundy ◽

Liljana Petrovska ◽

Gordon Dougan ◽

Stuart Knutton ◽

...

Keyword(s):

Escherichia Coli ◽

Type Iii Secretion ◽

Type Iii Secretion System ◽

Secretion System ◽

Effector Proteins ◽

Translocator Protein ◽

Type Iii ◽

Genes Encoding

ABSTRACT Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli are extracellular pathogens that employ a type III secretion system to export translocator and effector proteins, proteins which facilitates colonization of the mucosal surface of the intestine via formation of attaching and effacing (A/E) lesions. The genes encoding the proteins for A/E lesion formation are located on a pathogenicity island, termed the locus of enterocyte effacement (LEE), which contains eae encoding intimin as well as the type III secretion system and effector genes. Many type III secreted proteins are stabilized and maintained in a secretion-competent conformation in the bacterial cytosol by specific chaperone proteins. Three type III chaperones have been described thus far within the EPEC LEE region: CesD, for the translocator proteins EspB and EspD; CesT, for the effector proteins Tir and Map; and CesF, for EspF. In this study we report the characterization of CesD2 (previously Orf27), a second LEE-encoded chaperone for EspD. We show specific CesD2-EspD protein interaction which appears to be necessary for proper EspD secretion in vitro and pathogenesis in vivo as demonstrated in the A/E-lesion-forming mouse pathogen Citrobacter rodentium.

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Novel Effector Protein EspY3 of Type III Secretion System from Enterohemorrhagic Escherichia coli Is Localized in Actin Pedestals

Microorganisms ◽

10.3390/microorganisms6040112 ◽

2018 ◽

Vol 6 (4) ◽

pp. 112 ◽

Cited By ~ 2

Author(s):

Mariano Larzábal ◽

Wanderson Marques Da Silva ◽

Nahuel Riviere ◽

Ángel Cataldi

Keyword(s):

Escherichia Coli ◽

Type Iii Secretion ◽

Type Iii Secretion System ◽

Secretion System ◽

Effector Proteins ◽

Enterohemorrhagic Escherichia Coli ◽

Effector Protein ◽

Type Iii ◽

T3ss Effector ◽

Intestinal Enterocytes

Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic Escherichia coli (EPEC) are attaching and effacing (A/E) pathogens, which translocate effector proteins to intestinal enterocytes through a type III secretion system (T3SS). T3SS and most of its effector proteins are encoded in a pathogenicity island called LEE. Recently, new effectors have been located outside the LEE. This study aimed to characterize EspY3, a novel non-LEE encoded T3SS effector of EHEC. EspY3 shares homology with SopD and PipB2 effector proteins of Salmonella’s T3SS-1 and T3SS-2, respectively. The presence of recombinant EspY3 in the supernatant samples demonstrated that EspY3 was secreted by the T3SS of EHEC and EPEC. Through infection assays, we demonstrated the translocation of EspY3 into Caco-2 cells by T3SS of EPEC. The subcellular localization of EspY3 was determined in the pedestal region, where its presence generates a significant increase in the size of the pedestals area. The EspY3 effector induced the elongation of polymerized actin pedestals in infected Caco-2 by EPEC. This study confirmed that EspY3 is part of the repertoire of T3SS effectors of EHEC O157:H7, and that it participates in modeling cellular actin during the infection.

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CesAB is an enteropathogenic Escherichia coli chaperone for the type-III translocator proteins EspA and EspB

Microbiology ◽

10.1099/mic.0.26735-0 ◽

2003 ◽

Vol 149 (12) ◽

pp. 3639-3647 ◽

Cited By ~ 48

Author(s):

Elizabeth A. Creasey ◽

Devorah Friedberg ◽

Robert K. Shaw ◽

Tatiana Umanski ◽

Stuart Knutton ◽

...

Keyword(s):

Escherichia Coli ◽

Protein Interactions ◽

Type Iii Secretion ◽

Secretion System ◽

Effector Proteins ◽

Enteropathogenic Escherichia Coli ◽

Type Iii ◽

Mucosal Surfaces ◽

Enterocyte Effacement ◽

Bacterial Cytoplasm

Enteropathogenic Escherichia coli (EPEC) are extracellular pathogens that colonize mucosal surfaces of the intestine via formation of attaching and effacing (A/E) lesions. The genes responsible for induction of the A/E lesions are located on a pathogenicity island, termed the locus of enterocyte effacement (LEE), which encodes the adhesin intimin and the type III secretion system needle complex, translocator and effector proteins. One of the major EPEC translocator proteins, EspA, forms a filamentous conduit along which secreted proteins travel before they arrive at the translocation pore in the plasma membrane of the host cell, which is composed of EspB and EspD. Prior to secretion, many type III proteins, including translocators, are maintained in the bacterial cytoplasm by association with a specific chaperone. In EPEC, chaperones have been identified for the effector proteins Tir, Map and EspF, and the translocator proteins EspD and EspB. In this study, CesAB (Orf3 of the LEE) was identified as a chaperone for EspA and EspB. Specific CesAB–EspA and CesAB–EspB protein interactions are demonstrated. CesAB was essential for stability of EspA within the bacterial cell prior to secretion. Furthermore, a cesAB mutant failed to secrete EspA, as well as EspB, to assemble EspA filaments, to induce A/E lesion following infection of HEp-2 cells and to adhere to, or cause haemolysis of, erythrocytes.

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