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The effector repertoire of enteropathogenic E. coli: ganging up on the host cell.

Dean P, Kenny B - Curr. Opin. Microbiol. (2009)

Bottom Line: More recently, effectors encoded outside the LEE (non-LEE effectors) have been discovered and their functions are beginning to be uncovered.The recent completion of the EPEC genome sequence suggests its effector repertoire consists of at least 21 effector proteins.Here, we describe the genomic location of effectors and discuss recent advances made on effector cellular function as well as their role in the infection process.

View Article: PubMed Central - PubMed

Affiliation: Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Catherine Cookson Building, Framlington Place, Newcastle upon Tyne NE2 4HH, UK. p.dean@ncl.ac.uk

ABSTRACT
Diarrhoeal disease caused by enteropathogenic E. coli (EPEC) is dependent on a delivery system that injects numerous bacterial 'effector' proteins directly into host cells. The best-described EPEC effectors are encoded together on the locus of enterocyte effacement (LEE) pathogenicity island and display high levels of multifunctionality and cooperativity within the host cell. More recently, effectors encoded outside the LEE (non-LEE effectors) have been discovered and their functions are beginning to be uncovered. The recent completion of the EPEC genome sequence suggests its effector repertoire consists of at least 21 effector proteins. Here, we describe the genomic location of effectors and discuss recent advances made on effector cellular function as well as their role in the infection process.

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The six identified non-LEE effector encoding pathogenicity islands of EPEC E2348/69. Predicted effector genes were identified by mining the EPEC genome using over 400 known/predicted effector sequences. The identified effectors and genomic islands support the genome sequence published data (see text), from which the genomic island names were obtained. Only those genomic regions encoding the effectors and with low %GC content (graph above each island) are shown with most prophage-related genes surrounding these regions omitted. Genes and strand direction are shown by individual arrows which are drawn to scale within each island and colour coded (see inset). Multiple copies of genes are numbered according to close homologues in EHEC as explained in the legend to Table 1. Pseudogene key: (a) Cif; C-terminally truncated protein not produced or secreted in this EPEC strain [48]; (b) NleH3; C-terminal truncated; (c) NleO; no start codon; (d) EspL1; stop codon in middle of gene; (e) NleB3; N-terminal truncated.
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fig3: The six identified non-LEE effector encoding pathogenicity islands of EPEC E2348/69. Predicted effector genes were identified by mining the EPEC genome using over 400 known/predicted effector sequences. The identified effectors and genomic islands support the genome sequence published data (see text), from which the genomic island names were obtained. Only those genomic regions encoding the effectors and with low %GC content (graph above each island) are shown with most prophage-related genes surrounding these regions omitted. Genes and strand direction are shown by individual arrows which are drawn to scale within each island and colour coded (see inset). Multiple copies of genes are numbered according to close homologues in EHEC as explained in the legend to Table 1. Pseudogene key: (a) Cif; C-terminally truncated protein not produced or secreted in this EPEC strain [48]; (b) NleH3; C-terminal truncated; (c) NleO; no start codon; (d) EspL1; stop codon in middle of gene; (e) NleB3; N-terminal truncated.

Mentions: Whilst mining the EHEC (O157:H7 Sakai strain) genome sequence with over 200 known/predicted T3SS-dependent effector proteins, Pallen and colleagues identified 49 putative effectors [5]. At least 39 of these predicted proteins, of which many are homologues, were confirmed as secreted effectors in EHEC and include NleA-H (noting 12 NleG homologues) and newly described EspJ-O, EspR and EspV-Y effectors [5]. The recent completion of the EPEC genome sequence (strain E2348/69) enabled a similar ‘effector mining’ approach using an expanded list of over 400 known/predicted effector sequences and identified only 21 putative effectors (Dean and Kenny, unpublished; Table 1 and Figure 3). Thus, as recently reported [6•], EPEC appears to have a much smaller non-LEE effector repertoire than EHEC, encoding NleA-H (two homologues of B, E, H and only 1 of NleG), EspJ and EspL2, Orf3 (EspG2; which is the only EPEC effector so far identified that is not present in EHEC) and pseudogenes for NleH, EspO, NleB, EspL and Cif (Table 1 and Figure 3). Thus, whilst the LEE effector repertoire is well conserved, the set of non-LEE effectors is apparently flexible as EPEC strains B171-8 and E22 (rabbit-EPEC) possess 28 and 40 effectors, respectively, compared to 21 for the prototypical strain [6•].


The effector repertoire of enteropathogenic E. coli: ganging up on the host cell.

Dean P, Kenny B - Curr. Opin. Microbiol. (2009)

The six identified non-LEE effector encoding pathogenicity islands of EPEC E2348/69. Predicted effector genes were identified by mining the EPEC genome using over 400 known/predicted effector sequences. The identified effectors and genomic islands support the genome sequence published data (see text), from which the genomic island names were obtained. Only those genomic regions encoding the effectors and with low %GC content (graph above each island) are shown with most prophage-related genes surrounding these regions omitted. Genes and strand direction are shown by individual arrows which are drawn to scale within each island and colour coded (see inset). Multiple copies of genes are numbered according to close homologues in EHEC as explained in the legend to Table 1. Pseudogene key: (a) Cif; C-terminally truncated protein not produced or secreted in this EPEC strain [48]; (b) NleH3; C-terminal truncated; (c) NleO; no start codon; (d) EspL1; stop codon in middle of gene; (e) NleB3; N-terminal truncated.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC2697328&req=5

fig3: The six identified non-LEE effector encoding pathogenicity islands of EPEC E2348/69. Predicted effector genes were identified by mining the EPEC genome using over 400 known/predicted effector sequences. The identified effectors and genomic islands support the genome sequence published data (see text), from which the genomic island names were obtained. Only those genomic regions encoding the effectors and with low %GC content (graph above each island) are shown with most prophage-related genes surrounding these regions omitted. Genes and strand direction are shown by individual arrows which are drawn to scale within each island and colour coded (see inset). Multiple copies of genes are numbered according to close homologues in EHEC as explained in the legend to Table 1. Pseudogene key: (a) Cif; C-terminally truncated protein not produced or secreted in this EPEC strain [48]; (b) NleH3; C-terminal truncated; (c) NleO; no start codon; (d) EspL1; stop codon in middle of gene; (e) NleB3; N-terminal truncated.
Mentions: Whilst mining the EHEC (O157:H7 Sakai strain) genome sequence with over 200 known/predicted T3SS-dependent effector proteins, Pallen and colleagues identified 49 putative effectors [5]. At least 39 of these predicted proteins, of which many are homologues, were confirmed as secreted effectors in EHEC and include NleA-H (noting 12 NleG homologues) and newly described EspJ-O, EspR and EspV-Y effectors [5]. The recent completion of the EPEC genome sequence (strain E2348/69) enabled a similar ‘effector mining’ approach using an expanded list of over 400 known/predicted effector sequences and identified only 21 putative effectors (Dean and Kenny, unpublished; Table 1 and Figure 3). Thus, as recently reported [6•], EPEC appears to have a much smaller non-LEE effector repertoire than EHEC, encoding NleA-H (two homologues of B, E, H and only 1 of NleG), EspJ and EspL2, Orf3 (EspG2; which is the only EPEC effector so far identified that is not present in EHEC) and pseudogenes for NleH, EspO, NleB, EspL and Cif (Table 1 and Figure 3). Thus, whilst the LEE effector repertoire is well conserved, the set of non-LEE effectors is apparently flexible as EPEC strains B171-8 and E22 (rabbit-EPEC) possess 28 and 40 effectors, respectively, compared to 21 for the prototypical strain [6•].

Bottom Line: More recently, effectors encoded outside the LEE (non-LEE effectors) have been discovered and their functions are beginning to be uncovered.The recent completion of the EPEC genome sequence suggests its effector repertoire consists of at least 21 effector proteins.Here, we describe the genomic location of effectors and discuss recent advances made on effector cellular function as well as their role in the infection process.

View Article: PubMed Central - PubMed

Affiliation: Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Catherine Cookson Building, Framlington Place, Newcastle upon Tyne NE2 4HH, UK. p.dean@ncl.ac.uk

ABSTRACT
Diarrhoeal disease caused by enteropathogenic E. coli (EPEC) is dependent on a delivery system that injects numerous bacterial 'effector' proteins directly into host cells. The best-described EPEC effectors are encoded together on the locus of enterocyte effacement (LEE) pathogenicity island and display high levels of multifunctionality and cooperativity within the host cell. More recently, effectors encoded outside the LEE (non-LEE effectors) have been discovered and their functions are beginning to be uncovered. The recent completion of the EPEC genome sequence suggests its effector repertoire consists of at least 21 effector proteins. Here, we describe the genomic location of effectors and discuss recent advances made on effector cellular function as well as their role in the infection process.

Show MeSH
Related in: MedlinePlus