Limits...
Characterization of EhaJ, a New Autotransporter Protein from Enterohemorrhagic and Enteropathogenic Escherichia coli.

Easton DM, Totsika M, Allsopp LP, Phan MD, Idris A, Wurpel DJ, Sherlock O, Zhang B, Venturini C, Beatson SA, Mahony TJ, Cobbold RN, Schembri MA - Front Microbiol (2011)

Bottom Line: However, deletion of ehaJ did not significantly alter its adherence or biofilm properties.In summary, EhaJ is a new glycosylated AT protein from EPEC and EHEC.Further studies are required to elucidate the function of EhaJ in colonization and virulence.

View Article: PubMed Central - PubMed

Affiliation: School of Veterinary Science, The University of Queensland Gatton, QLD, Australia.

ABSTRACT
Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) are diarrheagenic pathotypes of E. coli that cause gastrointestinal disease with the potential for life-threatening sequelae. While certain EHEC and EPEC virulence mechanisms have been extensively studied, the factors that mediate host colonization remain to be properly defined. Previously, we identified four genes (ehaA, ehaB, ehaC, and ehaD) from the prototypic EHEC strain EDL933 that encode for proteins that belong to the autotransporter (AT) family. Here we have examined the prevalence of these genes, as well as several other AT-encoding genes, in a collection of EHEC and EPEC strains. We show that the complement of AT-encoding genes in EHEC and EPEC strains is variable, with some AT-encoding genes being highly prevalent. One previously uncharacterized AT-encoding gene, which we have termed ehaJ, was identified in 12/44 (27%) of EHEC and 2/20 (10%) of EPEC strains. The ehaJ gene lies immediately adjacent to a gene encoding a putative glycosyltransferase (referred to as egtA). Western blot analysis using an EhaJ-specific antibody indicated that EhaJ is glycosylated by EgtA. Expression of EhaJ in a recombinant E. coli strain, revealed EhaJ is located at the cell surface and in the presence of the egtA glycosyltransferase gene mediates strong biofilm formation in microtiter plate and flow cell assays. EhaJ also mediated adherence to a range of extracellular matrix proteins, however this occurred independent of glycosylation. We also demonstrate that EhaJ is expressed in a wild-type EPEC strain following in vitro growth. However, deletion of ehaJ did not significantly alter its adherence or biofilm properties. In summary, EhaJ is a new glycosylated AT protein from EPEC and EHEC. Further studies are required to elucidate the function of EhaJ in colonization and virulence.

No MeSH data available.


Related in: MedlinePlus

Genomic context of the group 6 autotransporter gene ehaJ and its associated glycosyltransferase gene egtA in EPEC 2348/69 genome (NC_011601) in comparison with K-12 strain MG1655 (NC_000913), EPEC 2787 (GU810159), and ETEC H10497 (FN649414). Whilst the arrangement of the glycosyltransferase upstream of the autotransporter gene is conserved, the genomic positions of these two genes are different in the four genomes. The figure was generated using Easyfig (http://easyfig.sourceforge.net/; Sullivan et al., 2011) with amino acid sequence comparison (tBLASTx). The level of amino acid identity is shown in the gradient scale.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3108271&req=5

Figure 1: Genomic context of the group 6 autotransporter gene ehaJ and its associated glycosyltransferase gene egtA in EPEC 2348/69 genome (NC_011601) in comparison with K-12 strain MG1655 (NC_000913), EPEC 2787 (GU810159), and ETEC H10497 (FN649414). Whilst the arrangement of the glycosyltransferase upstream of the autotransporter gene is conserved, the genomic positions of these two genes are different in the four genomes. The figure was generated using Easyfig (http://easyfig.sourceforge.net/; Sullivan et al., 2011) with amino acid sequence comparison (tBLASTx). The level of amino acid identity is shown in the gradient scale.

Mentions: The EPEC strain 2348/69 is the only genome sequenced E. coli strain in the NCBI database that contains the ehaJ gene (locus tag E2348C_2704). Further investigation of the EPEC E2348/69 genome revealed the presence of a gene encoding a putative glycosyltransferase immediately upstream of ehaJ (locus tag E2348C_2705), which we have referred to as EhaJ glycosyltransferase or egtA (Figure 1). This tandem glycosyltransferase-AT gene arrangement is similar to that observed for the AidA and TibA AT proteins (Benz and Schmidt, 1989; Elsinghorst and Kopecko, 1992). EhaJ shares 26.1% amino acid identity with AidA and 22.7% amino acid identity with TibA. Both the AidA and the TibA AT genes are located immediately downstream of a glycosyltransferase encoding gene (Figure 1). The tib locus also contains two additional genes, tibD and tibB, which have been suggested to play a role in regulation (Lindenthal and Elsinghorst, 1999). The predicted product of the egtA gene shares 63.9% amino acid identity with the TibC glycosyltransferase from ETEC H10407 (Elsinghorst and Weitz, 1994) and 62.1% amino acid identity with the AIDA-associated Aah heptosyltransferase from EPEC 2787 (Benz and Schmidt, 1989, 1992).


Characterization of EhaJ, a New Autotransporter Protein from Enterohemorrhagic and Enteropathogenic Escherichia coli.

Easton DM, Totsika M, Allsopp LP, Phan MD, Idris A, Wurpel DJ, Sherlock O, Zhang B, Venturini C, Beatson SA, Mahony TJ, Cobbold RN, Schembri MA - Front Microbiol (2011)

Genomic context of the group 6 autotransporter gene ehaJ and its associated glycosyltransferase gene egtA in EPEC 2348/69 genome (NC_011601) in comparison with K-12 strain MG1655 (NC_000913), EPEC 2787 (GU810159), and ETEC H10497 (FN649414). Whilst the arrangement of the glycosyltransferase upstream of the autotransporter gene is conserved, the genomic positions of these two genes are different in the four genomes. The figure was generated using Easyfig (http://easyfig.sourceforge.net/; Sullivan et al., 2011) with amino acid sequence comparison (tBLASTx). The level of amino acid identity is shown in the gradient scale.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108271&req=5

Figure 1: Genomic context of the group 6 autotransporter gene ehaJ and its associated glycosyltransferase gene egtA in EPEC 2348/69 genome (NC_011601) in comparison with K-12 strain MG1655 (NC_000913), EPEC 2787 (GU810159), and ETEC H10497 (FN649414). Whilst the arrangement of the glycosyltransferase upstream of the autotransporter gene is conserved, the genomic positions of these two genes are different in the four genomes. The figure was generated using Easyfig (http://easyfig.sourceforge.net/; Sullivan et al., 2011) with amino acid sequence comparison (tBLASTx). The level of amino acid identity is shown in the gradient scale.
Mentions: The EPEC strain 2348/69 is the only genome sequenced E. coli strain in the NCBI database that contains the ehaJ gene (locus tag E2348C_2704). Further investigation of the EPEC E2348/69 genome revealed the presence of a gene encoding a putative glycosyltransferase immediately upstream of ehaJ (locus tag E2348C_2705), which we have referred to as EhaJ glycosyltransferase or egtA (Figure 1). This tandem glycosyltransferase-AT gene arrangement is similar to that observed for the AidA and TibA AT proteins (Benz and Schmidt, 1989; Elsinghorst and Kopecko, 1992). EhaJ shares 26.1% amino acid identity with AidA and 22.7% amino acid identity with TibA. Both the AidA and the TibA AT genes are located immediately downstream of a glycosyltransferase encoding gene (Figure 1). The tib locus also contains two additional genes, tibD and tibB, which have been suggested to play a role in regulation (Lindenthal and Elsinghorst, 1999). The predicted product of the egtA gene shares 63.9% amino acid identity with the TibC glycosyltransferase from ETEC H10407 (Elsinghorst and Weitz, 1994) and 62.1% amino acid identity with the AIDA-associated Aah heptosyltransferase from EPEC 2787 (Benz and Schmidt, 1989, 1992).

Bottom Line: However, deletion of ehaJ did not significantly alter its adherence or biofilm properties.In summary, EhaJ is a new glycosylated AT protein from EPEC and EHEC.Further studies are required to elucidate the function of EhaJ in colonization and virulence.

View Article: PubMed Central - PubMed

Affiliation: School of Veterinary Science, The University of Queensland Gatton, QLD, Australia.

ABSTRACT
Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) are diarrheagenic pathotypes of E. coli that cause gastrointestinal disease with the potential for life-threatening sequelae. While certain EHEC and EPEC virulence mechanisms have been extensively studied, the factors that mediate host colonization remain to be properly defined. Previously, we identified four genes (ehaA, ehaB, ehaC, and ehaD) from the prototypic EHEC strain EDL933 that encode for proteins that belong to the autotransporter (AT) family. Here we have examined the prevalence of these genes, as well as several other AT-encoding genes, in a collection of EHEC and EPEC strains. We show that the complement of AT-encoding genes in EHEC and EPEC strains is variable, with some AT-encoding genes being highly prevalent. One previously uncharacterized AT-encoding gene, which we have termed ehaJ, was identified in 12/44 (27%) of EHEC and 2/20 (10%) of EPEC strains. The ehaJ gene lies immediately adjacent to a gene encoding a putative glycosyltransferase (referred to as egtA). Western blot analysis using an EhaJ-specific antibody indicated that EhaJ is glycosylated by EgtA. Expression of EhaJ in a recombinant E. coli strain, revealed EhaJ is located at the cell surface and in the presence of the egtA glycosyltransferase gene mediates strong biofilm formation in microtiter plate and flow cell assays. EhaJ also mediated adherence to a range of extracellular matrix proteins, however this occurred independent of glycosylation. We also demonstrate that EhaJ is expressed in a wild-type EPEC strain following in vitro growth. However, deletion of ehaJ did not significantly alter its adherence or biofilm properties. In summary, EhaJ is a new glycosylated AT protein from EPEC and EHEC. Further studies are required to elucidate the function of EhaJ in colonization and virulence.

No MeSH data available.


Related in: MedlinePlus