has role has_role has role gene as virulence factor in pathogen gene mutant attenuated in host cell line cell gene mutant attenuated in host cell gene mutant attenuated in host has role has_role has role HeLa cell HeLa cell HeLa 细胞 macrophage macrophage 巨噬细胞 Mus musculus Mus musculus 小家鼠 Brucella melitensis bv. 1 str. 16M protein-coding gene of Brucella melitensis bv. 1 str. 16M BMEII0025 1197796 20140217 224914 BMEII0025 Bin Zhao, Oliver He II NCBI-supplied PMID: 11756688; 12271122 WEB: http://www.ncbi.nlm.nih.gov/gene attachment mediating protein VIRB1-like protein protein-coding 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 virB1 mutant persisted at wild-type levels, showing that the function of VirB1 is dispensable in the mouse model of persistent infection [PMID:15322008]. A B abortus polar virB1 mutant failed to replicate in HeLa cells, indicating that the virB operon plays a critical role in intracellular multiplication [PMID:15322008]. 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 [PMID:15322008]. An infection assay with signature-tagged Brucella abortus mutants demonstrated that mutagenesis of the virB1 gene causes attenuation of virulence [PMID:15322008]. 1328 virulence factor gene role