title: The role of the vacB gene in the pathogenesis of Brucella abortus.
abstract: Brucella species are important zoonotic pathogens affecting a wide variety of mammals. Therefore, the identification of new Brucella virulence factors is of great interest in understanding bacterial pathogenesis and immune evasion. In this study, we have identified Brucella abortus vacB gene that presents 2343 nucleotides and 781 amino acids and it shows 39% identity with Shigella flexneri vacB gene that encodes an exoribonuclease RNase R involved in bacterial virulence. Further, we have inactivated Brucella vacB by gene replacement strategy generating a deletion mutant strain. In order to test the role of Brucella vacB in pathogenesis, BALB/c and interferon regulatory factor-1 (IRF-1) knockout (KO) mice received Brucella vacB mutant, the virulent parental strain 2308 or the vaccine strain RB51 and the bacterial CFU numbers in spleens and mous survival were monitored. Our results demonstrated that the B. abortus DeltavacB mutant and the wild type strain 2308 showed similar CFU numbers in BALB/c mice. Additionally, IRF-1 KO mice that received either the vacB mutant or S2308 strain died in 12-14 days postinfection; in contrast, all animals that received the RB51 vaccine strain survived for 30 days postinoculation. In summary, this study reports that the vacB gene in B. abortus has no impact on bacterial pathogenesis.
authors.affiliation: Department of General Biology, Federal University of Minas Gerais, Minas Gerais, Pampulha, Belo Horizonte, MG, Brazil.
authors.forename: Anderson
authors.initials: A
authors.lastname: Miyoshi
authors.forename: Gracia M S
authors.initials: GM
authors.lastname: Rosinha
authors.forename: Ilana L B C
authors.initials: IL
authors.lastname: Camargo
authors.forename: Cyntia M C
authors.initials: CM
authors.lastname: Trant
authors.forename: Fernanda C
authors.initials: FC
authors.lastname: Cardoso
authors.forename: Vasco
authors.initials: V
authors.lastname: Azevedo
authors.forename: Sergio C
authors.initials: SC
authors.lastname: Oliveira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002004:Brucella Vaccine / Q000008:administration & dosage; D002003:Brucella abortus / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D002006:Brucellosis / Q000276:immunology / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control; D005095:Exoribonucleases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005260:Female; D017353:Gene Deletion; D006801:Humans; D050856:Interferon Regulatory Factor-1 / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013154:Spleen / Q000382:microbiology; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D002004:Brucella Vaccine; D050856:Interferon Regulatory Factor-1; D005095:Exoribonucleases; C080868:ribonuclease R