Differential requirements for VirB1 and VirB2 during Brucella abortus infection

Andreas B. Den Hartigh, Yao Hui Sun, David Sondervan, Niki Heuvelmans, Marjolein O. Reinders, Thomas A. Ficht, Renee M Tsolis

Research output: Contribution to journalArticlepeer-review

79 Scopus citations


The Brucella abortus virB operon, encoding a type IV secretion system (T4SS), is required for intracellular replication and persistent infection in the mouse model. The products of the first two genes of the virB operon, virB1 and virB2, are predicted to be localized at the bacterial surface, where they could potentially interact with host cells. Studies to date have focused on characterization of transposon mutations in these genes, which are expected to exert polar effects on downstream genes in the operon. In order to determine whether VirB1 and VirB2 are required for the function of the T4SS apparatus, we constructed and characterized nonpolar deletion mutations of virB1 and virB2. Both mutants were shown to be nonpolar, as demonstrated by their ability to express the downstream gene virB5 during stationary phase of growth in vitro. Both VirB1 and VirB2 were essential for intracellular replication in J774 macrophages. The nonpolar virB2 mutant was unable to cause persistent infection in the mouse model, demonstrating the essential role of VirB2 in the function of the T4SS apparatus during infection. In contrast, the nonpolar virB1 mutant persisted at wild-type levels, showing that the function of VirB1 is dispensable in the mouse model of persistent infection.

Original languageEnglish (US)
Pages (from-to)5143-5149
Number of pages7
JournalInfection and Immunity
Issue number9
StatePublished - Sep 2004
Externally publishedYes

ASJC Scopus subject areas

  • Immunology


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