title: relA enhances the adherence of enteropathogenic Escherichia coli.
abstract: Enteropathogenic Escherichia coli (EPEC) is a known causative agent of diarrhea in children. In the process of colonization of the small intestine, EPEC synthesizes two types of adhesins, the bundle-forming pilus (BFP) and intimin. The BFP pilus is an adhesin associated with the initial stages of adherence of EPEC to epithelial cells, while the outer membrane protein intimin carries out the intimate adherence that takes place at the third stage of infection. BFP is encoded by the bfp operon located in plasmid EAF, present only in typical EPEC isolates, while eae, the gene that encodes intimin is situated in the LEE, a chromosomal pathogenicity island. Transcription of bfp and eae is regulated by the products of the perABC operon, also present in plasmid EAF. Here we show that deletion of relA, that encodes a guanosine penta and tetraphosphate synthetase impairs EPEC adherence to epithelial cells in vitro. In the absence of relA, the transcription of the regulatory operon perABC is reduced, resulting in lower levels of BFP and intimin. Bacterial adherence, BFP and intimin synthesis and perABC expression are restored upon complementation with the wild-type relA allele.
authors.affiliation: Departamento de Microbiologia, Instituto de Cêincias Biomédicas, Universidade de São Paulo, São Paulo-SP, Brazil.
authors.forename: Beny
authors.initials: B
authors.lastname: Spira
authors.affiliation: Departamento de Microbiologia, Instituto de Cêincias Biomédicas, Universidade de São Paulo, São Paulo-SP, Brazil.
authors.forename: Gerson Moura
authors.initials: GM
authors.lastname: Ferreira
authors.affiliation: Departamento de Microbiologia, Instituto de Cêincias Biomédicas, Universidade de São Paulo, São Paulo-SP, Brazil.
authors.forename: Luiz Gustavo
authors.initials: LG
authors.lastname: de Almeida
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics* / Q000378:metabolism; D001422:Bacterial Adhesion; D054308:Enteropathogenic Escherichia coli / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D036781:Fimbriae Proteins / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D044404:Genomic Islands; D008025:Ligases / Q000172:deficiency / Q000235:genetics*; D009876:Operon; D021122:Protein Subunits / Q000235:genetics* / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; C104901:BfpA protein, E coli; D029968:Escherichia coli Proteins; D021122:Protein Subunits; C073819:eaeA protein, E coli; D036781:Fimbriae Proteins; D008025:Ligases; C028812:guanosine 3',5'-polyphosphate synthetases