PMID:27191515

Citation	Chaparian, RR, Olney, SG, Hustmyer, CM, Rowe-Magnus, DA and van Kessel, JC (2016) Integration host factor and LuxR synergistically bind DNA to coactivate quorum-sensing genes in Vibrio harveyi. Mol. Microbiol. 101:823-40
Abstract	The cell-cell signaling process called quorum sensing allows bacteria to control behaviors in response to changes in population density. In Vibrio harveyi, the master quorum-sensing transcription factor LuxR is a member of the TetR family of transcription factors that both activates and represses genes to coordinate group behaviors, including bioluminescence. Here, we show that integration host factor (IHF) is a key coactivator of the luxCDABE bioluminescence genes that is required together with LuxR for precise timing and expression levels of bioluminescence during quorum sensing. IHF binds to multiple sites in the luxCDABE promoter and bends the DNA in vitro. IHF and LuxR synergistically bind luxCDABE promoter DNA at overlapping, essential binding sites that are required for maximal gene expression in vivo. RNA-seq analysis demonstrated that IHF regulates 300 genes in V. harveyi, and among these are a core set of 19 genes that are also directly bound and regulated by LuxR. We validated these global analyses by demonstrating that both IHF and LuxR are required for transcriptional activation of the osmotic stress response genes betIBA-proXWV. These data suggest that IHF plays an integral role in one mechanism of transcriptional activation by the LuxR-type family of quorum-sensing regulators in vibrios.
Links	PubMed Online version:10.1111/mmi.13425
Keywords	Bacterial Proteins/metabolism; Binding Sites; DNA, Bacterial/genetics; DNA, Bacterial/metabolism; Gene Expression Regulation, Bacterial/genetics; Integration Host Factors/metabolism; Luminescent Proteins/genetics; Luminescent Proteins/metabolism; Promoter Regions, Genetic; Quorum Sensing/genetics; Repressor Proteins/genetics; Repressor Proteins/metabolism; Sequence Analysis, DNA/methods; Signal Transduction/genetics; Trans-Activators/genetics; Trans-Activators/metabolism; Transcription Factors/metabolism; Vibrio/genetics; Vibrio/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
VIBHA:LUXR		GO:0003700: DNA-binding transcription factor activity	ECO:0001807: electrophoretic mobility shift assay evidence used in manual assertion		F		Figure 3D shows Electrophoretic Mobility Shift Assays that depict the binding of master quorum sensing transcription factor LuxR to the LuxC promoter region of Vibrio harveyi Should have GenBank:X07084.1 in the with/from field Updated GO term: see Discussion page	complete CACAO 13525
VIBCB:IHFA		GO:1905087: positive regulation of bioluminescence	ECO:0000315:		P		Figure 2C shows that "strains that expressed ihfA or ihfB complemented bioluminescence ~10-fold above the vector control strain (Fig. 2C)." Indicating that IHF is required for bioluminescence genes. Organism: Vibrio harveyi	complete CACAO 13163
VIBCB:IHFB		GO:1905087: positive regulation of bioluminescence	ECO:0000315:		P		Figure 2C shows that "strains that expressed ihfA or ihfB complemented bioluminescence ~10-fold above the vector control strain (Fig. 2C)." Indicating that IHF is required for bioluminescence genes. Organism: Vibrio harveyi	complete CACAO 13164

References

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