title: Expression and activity of the cytolethal distending toxin of Helicobacter hepaticus.
abstract: Helicobacter hepaticus, a causal agent of hepatocarcinoma in mice, exhibits a cytolethal distending toxin activity. The three subunits of this holotoxin, CdtA, CdtB, and CdtC, and three CdtB mutants were produced as recombinant histidine-tagged proteins by using an in vitro cell-free protein expression system. We found that the presence of the three H. hepaticus Cdt subunits is required for cellular toxicity and that only a C-terminal CdtB mutation abolishes the activity of the complex. In vitro, H. hepaticus CdtB exhibits a DNase activity which is also abolished by this C-terminal CdtB mutation. These results suggest that the effect of H. hepaticus CDT probably involves the DNase activity of CdtB.
authors.affiliation: Laboratoire de Bactériologie EA3667, Université Victor Segalen Bordeaux 2, Bordeaux, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Avenaud
authors.forename: Michel
authors.initials: M
authors.lastname: Castroviejo
authors.forename: Sandra
authors.initials: S
authors.lastname: Claret
authors.forename: Jean
authors.initials: J
authors.lastname: Rosenbaum
authors.forename: Francis
authors.initials: F
authors.lastname: Mégraud
authors.forename: Armelle
authors.initials: A
authors.lastname: Ménard
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000633:toxicity*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003851:Deoxyribonucleases / Q000378:metabolism; D015870:Gene Expression; D044923:Helicobacter hepaticus / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000166:cytology; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000633:toxicity; D016415:Sequence Alignment
chemical_list: D001427:Bacterial Toxins; D021122:Protein Subunits; D011994:Recombinant Proteins; C067044:cytolethal distending toxin; D003851:Deoxyribonucleases