PMID:22233679

Citation	Cao, X, Studer, SV, Wassarman, K, Zhang, Y, Ruby, EG and Miyashiro, T (2012) The novel sigma factor-like regulator RpoQ controls luminescence, chitinase activity, and motility in Vibrio fischeri. MBio 3
Abstract	Vibrio fischeri, the bacterial symbiont of the Hawaiian bobtail squid, Euprymna scolopes, uses quorum sensing to control genes involved in bioluminescence, host colonization, and other biological processes. Previous work has shown that AinS/R-directed quorum sensing also regulates the expression of rpoQ (VF_A1015), a gene annotated as an RpoS-like sigma factor. In this study, we demonstrate using phylogenetics that RpoQ is related to, but distinct from, the stationary-phase sigma factor RpoS. Overexpression of rpoQ results in elevated chitinase activity but decreased motility and luminescence, three activities associated with symbiosis. The reduction in bacterial luminescence associated with the overexpression of rpoQ occurs both in culture and within the light-emitting organ of the squid host. This suppression of bioluminescence is due to the repression of the luxICDABEG promoter. Our results highlight RpoQ as a novel regulatory component, embedded in the quorum-signaling network that controls several biological processes in V. fischeri. IMPORTANCE: Quorum signaling is a widely occurring phenomenon that functions in diverse bacterial taxa. It is most often found associated with species that interact with animal or plant hosts, either as mutualists or pathogens, and controls the expression of genes critical to tissue colonization. We present the discovery of rpoQ, which encodes a new regulatory component in the quorum-signaling pathway of Vibrio fischeri. RpoQ is a novel protein in the RpoS family of stationary-phase sigma factors. Unlike many other regulatory proteins involved in the quorum-signaling pathways of the Vibrionaceae, the distribution of RpoQ appears to be restricted to only two closely related species. The role of this regulator is to enhance some quorum-signaling outputs (motility) while suppressing others (luminescence). We propose that RpoQ may be a recently evolved or acquired component in V. fischeri that provides this organism with an additional level of regulation to modulate its existing quorum-signaling pathway.
Links	PubMed PMC3252764 Online version:10.1128/mBio.00285-11
Keywords	Aliivibrio fischeri/genetics; Aliivibrio fischeri/isolation & purification; Aliivibrio fischeri/physiology; Animals; Chitinase/metabolism; Decapodiformes/microbiology; Decapodiformes/physiology; Gene Deletion; Gene Expression; Gene Expression Regulation, Bacterial; Locomotion; Luminescence; Luminescent Proteins/metabolism; Models, Biological; Quorum Sensing; Symbiosis; Transcription Factors/genetics; Transcription Factors/metabolism
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
VIBF1:Q5DYR1		GO:2000146: negative regulation of cell motility	ECO:0000315:		P		Figure 7 shows that strains of V. fischeri that overexpress RpoQ have reduced motility	complete CACAO 5292
VIBF1:Q5DYR1		GO:0045892: negative regulation of transcription, DNA-dependent	ECO:0000315:		P		Figure 6 shows that V. fischeri that overexpress RpoQ have lowered expression levels of luxICDABEG	complete CACAO 5293
VIBF1:Q5DYR1		GO:0035885: exochitinase activity	ECO:0000315:		F		Figure 8A. The ΔrpoQ mutant showed chitinase activity that was significantly lower than the wild type. Both the wild type and the ΔrpoQ mutant overexpressing RpoQ showed chitinase activity that was 2.3- to 2.8-fold-higher.	complete CACAO 8658
VIBF1:Q5DYR1	involved_in	GO:0045892: negative regulation of transcription, DNA-templated	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
VIBF1:Q5DYR1	enables	GO:0035885: exochitinase activity	ECO:0000315: mutant phenotype evidence used in manual assertion		F		Seeded From UniProt	complete

References

See Help:References for how to manage references in GONUTS.