PMID:19019140

Citation	de Jong, MF, Sun, YH, den Hartigh, AB, van Dijl, JM and Tsolis, RM (2008) Identification of VceA and VceC, two members of the VjbR regulon that are translocated into macrophages by the Brucella type IV secretion system. Mol. Microbiol. 70:1378-96
Abstract	Survival and replication inside host cells by Brucella spp. requires a type IV secretion system (T4SS), encoded by the virB locus. However, the identity of the molecules secreted by the T4SS has remained elusive. We hypothesized that proteins translocated by the T4SS would be co-regulated with the virB operon. The LuxR family regulator VjbR, known to regulate virB, bound a fragment of the virB promoter containing an 18 bp palindromic motif (virB promoter box), showing that VjbR regulated the virB operon directly. To identify virB co-regulated genes, we searched the Brucella suis 1330 and B. abortus 2308 genomes for genes with an upstream virB promoter box. One hundred and forty-four promoters in the two genomes contained the virB promoter box, including those of fliC encoding flagellin and cgs encoding cyclic beta-glucan synthetase. Thirteen of these proteins were tested for VirB-dependent translocation into macrophages using a beta-lactamase reporter assay. This analysis resulted in the identification of the proteins encoded by BAB1_1652 (VceA) and BR1038/BAB1_1058 (VceC) as novel protein substrates of the Brucella T4SS. VceC could also be translocated by the Legionella pneumophila Dot/Icm T4SS into host cells. Our results suggest that VjbR co-ordinates expression of the T4SS and at least two of its secreted substrates.
Links	PubMed PMC2993879 Online version:10.1111/j.1365-2958.2008.06487.x
Keywords	Amino Acid Sequence; Animals; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Base Sequence; Brucella abortus/genetics; Brucella abortus/metabolism; Brucella suis/genetics; Brucella suis/metabolism; Cell Line; Consensus Sequence; Electrophoretic Mobility Shift Assay; Escherichia coli/genetics; Escherichia coli/metabolism; Gene Expression Regulation, Bacterial; Genetic Complementation Test; Macrophages/metabolism; Macrophages/microbiology; Mice; Molecular Sequence Data; Promoter Regions, Genetic; Protein Structure, Tertiary; Protein Transport; Regulon; Secretory Pathway/genetics
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
BRUA2:Q2YQ34		GO:0052050: interaction with host via substance secreted by type IV secretion system	ECO:0000314:		P		Figure 7. Translocation of TEM1::VceA and TEM1::VceC into J774 macrophages. Cytosolic translocation of b-lactamase by wild type (2308) or virB2 mutant strain (ADH3) of B. abortus was assessed by fluorescence microscopy. Cells in which translocation of the fusion protein has occurred appear blue. Shows translocation of effector protein VceC (BAB1_1058) by VirB-T4SS. Figure 8. Translocation of TEM1::VceA and TEM1::VceC into J774 macrophages at different time points after infection. Shows translocation of effector protein VceC (BAB1_1058) by VirB-T4SS during Brucella abortus infection.	complete CACAO 11037
BRUA2:Q2YRI6		GO:0052050: interaction with host via substance secreted by type IV secretion system	ECO:0000314:		P		Figure 7. Translocation of TEM1::VceA and TEM1::VceC into J774 macrophages. Cytosolic translocation of b-lactamase by wild type (2308) or virB2 mutant strain (ADH3) of B. abortus was assessed by fluorescence microscopy. Cells in which translocation of the fusion protein has occurred appear blue. Shows translocation of effector protein VceA (BAB1_1652) by VirB-T4SS. Figure 8. Translocation of TEM1::VceA and TEM1::VceC into J774 macrophages at different time points after infection. Shows translocation of effector protein VceA (BAB1_1652) by VirB-T4SS during Brucella abortus infection.	complete CACAO 11038
BRUSU:A0A0H3GG90		GO:0052050: interaction with host via substance secreted by type IV secretion system	ECO:0000314:		P		Figure 7. Translocation of TEM1::VceA and TEM1::VceC into J774 macrophages. Cytosolic translocation of b-lactamase by wild type (2308) or virB2 mutant strain (ADH3) of B. abortus was assessed by fluorescence microscopy. Cells in which translocation of the fusion protein has occurred appear blue. Shows translocation of effector protein VceC (BR1038) from Brucella suis strain 1330 by VirB-T4SS. Figure 8. Translocation of TEM1::VceA and TEM1::VceC into J774 macrophages at different time points after infection. Shows translocation of effector protein VceC (BAR1038) from Brucella suis strain 1330 by VirB-T4SS during Brucella abortus infection.	complete CACAO 11152

References

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