Characterization of the eaeA gene from rabbit enteropathogenic Escherichia coli strain RDEC-1 and comparison to other eaeA genes from bacteria that cause attaching-effacing lesions.
A number of enteric pathogens, including enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli, Hafnia alvei, a strain of Citrobacter freundii, and rabbit EPEC strain RDEC-1 cause attaching-effacing (AE) lesions in the gut mucosa. These bacteria have a pathogenicity cassette (locus of enterocyte effacement or LEE) containing the eaeA gene. This gene encodes intimin, an outer membrane protein required for production of AE lesions. RDEC-1, a non-invasive enteropathogen in young rabbits, produces AE lesions morphologically indistinguishable from lesions caused by human AE bacterial strains. The RDEC-1 example of E. coli diarrhea in rabbits is an important model for studying the pathogenesis of AE bacteria in a natural infection and for analyzing specific roles of the components of LEE. In order to better understand the role of intimin in the development of AE lesions, a portion of DNA within RDEC-1 LEE, containing the eaeA gene and an upstream open reading frame (ORF), was sequenced. The RDEC-1 eaeA gene shared 87%, 92%, and 93% DNA sequence identity and > 80% amino acid sequence identity with the eaeA genes of C. freundii biotype 4280, EHEC O157:H7, and EPEC O127:116, respectively. The carboxy-terminal 280 amino acid residues of intimin has 80%, 56%, and 54% identity with C. freundii, EHEC O157:H7, and EPEC O127:H6 intimins, respectively. The predicted protein encoded by the upstream ORF (156 amino acids) shares 95%, 97%, and 99% amino acid identity with predicted proteins from C. freundii. EHEC O157:H7, and EPEC O127:H6, respectively. The high degree of sequence homology of the ORF and the eueA gene of RDEC-1 with those of other AE bacteria suggests an evolutionary relationship of LEE and supports and facilitates the use of the RDEC-1 model for studying the role of LEE in pathogenesis.
Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA.
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Agin
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Cantey
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Boedeker
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Wolf
D018829:Adhesins, Bacterial; D000595:Amino Acid Sequence; D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins; D003967:Diarrhea / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D004195:Disease Models, Animal; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D029968:Escherichia coli Proteins; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011817:Rabbits; D013045:Species Specificity
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C073819:eaeA protein, E coli