PMID:12675810

Citation	Miyamoto, CM, Dunlap, PV, Ruby, EG and Meighen, EA (2003) LuxO controls luxR expression in Vibrio harveyi: evidence for a common regulatory mechanism in Vibrio. Mol. Microbiol. 48:537-48
Abstract	Quorum-sensing control of luminescence in Vibrio harveyi, which involves an indirect autoinducer-mediated phosphorelay signal transduction system, contrasts with the prototypical quorum-sensing system of Vibrio fischeri, in which the autoinducer and the transcriptional activator LuxR directly activate lux operon expression. In V. harveyi, a regulator not homologous to V. fischeri LuxR and also designated LuxR (LuxRvh), binds specifically to the lux operon promoter region and activates the expression of luminescence. A direct connection has not been identified previously between V. harveyi LuxRvh and the autoinducer-mediated phosphorelay system. Here, we demonstrate by mobility shift assays and measurement of luxRvh mRNA levels with luxO+ and luxO- cells that the central response regulator of the V. harveyi phosphorelay system (LuxO) represses the level of LuxRvh. Expression of a luxRvh-bearing plasmid strongly stimulated luminescence of a luxO- mutant but had no effect on luminescence of wild-type luxO+ cells, indicating tight regulation of luxRvh by LuxO. Furthermore, luxO null mutants of V. fischeri MJ-1 and two autoinducer mutants, MJ-211 (luxI-) and MJ-215 (luxI-ainS-), emitted more light and exhibited more elevated levels of litR, a newly identified V. harveyi luxRvh homologue, than their luxO+ counterparts. These results suggest that activity of the autoinducer-mediated phosphorelay system is coupled to LuxRvh/LitR control of luminescence through LuxO in V. harveyi and V. fischeri. The presence of homologues of V. harveyi LuxRvh, LuxO and other phosphorelay system proteins in various Vibrio species and the control of LuxRvh and its homologues by LuxO identified here in V. harveyi and V. fischeri and recently in Vibrio cholerae suggest that the luxO-luxRvh couple is a central feature of this quorum-sensing system in members of the genus Vibrio.
Links	PubMed
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Gene Expression Regulation, Bacterial; Genes, Regulator; Genotype; Hydroxybutyrates/metabolism; Luminescent Measurements; Mutation; Promoter Regions, Genetic; RNA, Messenger/metabolism; Repressor Proteins/genetics; Repressor Proteins/metabolism; Signal Transduction/physiology; Trans-Activators/genetics; Trans-Activators/metabolism; Transcription Factors/genetics; 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:LUXO	involved_in	GO:0008218: bioluminescence	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
VIBHA:LUXO		GO:0008218: bioluminescence	ECO:0000315:		P		In Figure 4, the presence of luxRvh strongly stimulated luminescence in the V. harveyi luxO null mutant	complete CACAO 9165

References

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