title: fur-independent regulation of the Pasteurella multocida hbpA gene encoding a haemin-binding protein.
abstract: Treatment of bacterial cultures with chelating agents such as 2,2'-dipyridyl (DPD) induces expression of iron-regulated genes. It is known that in the gamma-Proteobacteria, the Fur protein is the major regulator of genes encoding haem- or haemoglobin-binding proteins. Electrophoretic analysis of outer-membrane proteins of the gamma-proteobacterium Pasteurella multocida has revealed the induction of two proteins of 60 and 40 kDa in DPD-treated cultures in both wild-type and fur-defective strains. These two proteins have the same N-terminal amino acid sequence, which identifies this protein as the product of the PM0592 ORF. Analysis of the sequence of this ORF, which encodes a protein of 60 kDa, revealed the presence of a hexanucleotide (AAAAAA) at which a programmed translational frameshift can occur giving rise to a 40 kDa protein. Analyses conducted in Escherichia coli, using the complete PM0592 ORF and a derivative truncated at the hexanucleotide position, have shown that both polypeptides bind haemin. For this reason, the PM0592 ORF product has been designated HbpA (for haemin-binding protein). Expression studies using both RT-PCR and lacZ fusions, as well as electrophoretic profiles of outer-membrane protein composition, have demonstrated that the hbpA gene is negatively regulated by iron, manganese and haemin through a fur-independent pathway. Despite the fact that serum of mice infected with P. multocida contained antibodies that reacted with both the 60 and 40 kDa products of the hbpA gene, these proteins did not offer protection when used in immunization assays against this micro-organism.
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, 08193 - Barcelona, Spain.
authors.forename: M Elena
authors.initials: ME
authors.lastname: Garrido
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, 08193 - Barcelona, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Bosch
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, 08193 - Barcelona, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Medina
authors.affiliation: Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, 08193 - Barcelona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Bigas
authors.affiliation: Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona, Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA), Bellaterra, 08193 - Barcelona, Spain.|Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, 08193 - Barcelona, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Llagostera
authors.affiliation: Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona, Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA), Bellaterra, 08193 - Barcelona, Spain.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Pérez de Rozas
authors.affiliation: Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona, Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA), Bellaterra, 08193 - Barcelona, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Badiola
authors.affiliation: Centre de Recerca en Sanitat Animal (CReSA), Universitat Autònoma de Barcelona, Institut de Recerca i Tecnologia Agroalimentària (UAB-IRTA), Bellaterra, 08193 - Barcelona, Spain.|Department of Genetics and Microbiology, Universitat Autònoma de Barcelona, Bellaterra, 08193 - Barcelona, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Barbé
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D016979:Pasteurella multocida / Q000235:genetics* / Q000276:immunology / Q000378:metabolism* / Q000472:pathogenicity; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial