has_part has part has_part has disposition at some time B. abortus virB2 mutant attenuated disposition B. melitensis 16M virB2 mutant A mutant of strain Brucella melitensis bv. 1 str. 16M that lacks an intact gene virB2. UniProtKB accession: Q9RPY3 Information about the mutated molecule: MUTATION: 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. 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 [Ref6539:den et al., 2004]. Polar mutations in the virB1 to virB2 intergenic region or in virB2 reduced the detection of VirB5 to a greater extent than they did that of VirB12. A virB1 mutation also eliminates the transcription of virB12 in B suis [Ref6470:Sun et al., 2005]. YH PMID: 15322008, 16113325 The gene virB2 from the strain Brucella melitensis bv. 1 str. 16M is a virulence gene. NCBIGene: 1197797 BMEII0026 VirB2