title: Haemagglutinin/protease expression and mucin gel penetration in El Tor biotype Vibrio cholerae.
abstract: Vibrio cholerae of both biotypes produce a soluble Zn(2+)-dependent metalloprotease: haemagglutinin/protease (Hap), encoded by hapA. Hap has been shown to have mucinolytic and cytotoxic activity. These activities are likely to play an important role in the pathogenesis of cholera and the reactogenicity of attenuated vaccine strains. Production of Hap requires transcriptional activation by the HapR regulator and is repressed by glucose. The present study shows that mucin purified from two sources, bile salts, and growth at 37 degrees C enhanced Hap protease production. Analysis of hapA and hapR promoter fusions with the lacZ gene showed both promoters to be activated in a cell-density-dependent pattern. Glucose repressed and mucin induced the hapA promoter by a HapR-independent mechanism. Bile had no effect on either hapR or hapA promoter activity. Expression of hapA was required for vibrios to translocate through a mucin-containing gel. These results suggest Hap to play an important role in cholera pathogenesis by promoting mucin gel penetration, detachment and spreading of infection along the gastrointestinal tract.
authors.affiliation: California State University College of Science and Mathematics, Department Biology, 2555 East San Ramon Avenue, Fresno, CA 93740, USA.
authors.forename: Anisia J
authors.initials: AJ
authors.lastname: Silva
authors.affiliation: California State University College of Science and Mathematics, Department Biology, 2555 East San Ramon Avenue, Fresno, CA 93740, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: Pham
authors.affiliation: Morehouse School of Medicine Department of Microbiology, Biochemistry and Immunology, 720 Westview Dr, SW, Atlanta, GA 30310-1495, USA.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Benitez
mesh_terms: D015373:Bacterial Typing Techniques; D001483:Base Sequence; D001646:Bile / Q000382:microbiology; D002771:Cholera / Q000209:etiology; D004269:DNA, Bacterial / Q000235:genetics; D005782:Gels; D015870:Gene Expression / Q000187:drug effects; D005798:Genes, Bacterial; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007763:Lac Operon; D008666:Metalloendopeptidases / Q000235:genetics*; D009077:Mucins / Q000235:genetics; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D014734:Vibrio cholerae / Q000145:classification / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D014774:Virulence
chemical_list: D004269:DNA, Bacterial; D005782:Gels; D009077:Mucins; D008666:Metalloendopeptidases; C039814:hemagglutinin-protease; D005947:Glucose