Quorum regulation of luminescence in Vibrio fischeri.
Luminescence in Vibrio fischeri is controlled by a population density-responsive regulatory mechanism called quorum sensing. Elements of the mechanism include: LuxI, an acyl-homoserine lactone (acyl-HSL) synthase that directs synthesis of the diffusible signal molecule, 3-oxo-hexanoyl-HSL (V. fischeri autoinducer-1, VAI-1); LuxR, a transcriptional activator protein necessary for response to VAI-1; GroEL, which is necessary for production of active LuxR; and AinS, an acyl-HSL synthase that catalyzes the synthesis of octanoyl-HSL (VAI-2). The population density-dependent accumulation of VAI-1 triggers induction of lux operon (luxICDABEG; genes for luminescence enzymes and for LuxI) transcription and luminescence by binding to LuxR, forming a complex that facilitates the association of RNA polymerase with the luxoperon promoter. VAI-2, which apparently interferes with VAI-1 binding to LuxR, operates to limit premature luxoperon induction. Hierarchical control is imposed on the system by 3':5'-cyclic AMP (cAMP) and cAMP receptor protein (CRP), which are necessary for activated expression of luxR. Several non-lux genes in V. fischeri are controlled by LuxR and VAI-1. Quorum regulation in V. fischeri serves as a model for LuxI/LuxR-type quorum sensing systems in other gram-negative bacteria.
Dunlap
P V
PV
Center of Marine Biotechnology, University of Maryland, Biotechnology Institute, Baltimore 21202, USA. dunlap@umbi.umd.edu
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000096:biosynthesis; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D005798:Genes, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives; D007783:Lactones; D008163:Luminescent Measurements; D008958:Models, Molecular; D012097:Repressor Proteins / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014733:Vibrio / Q000378:metabolism*
C096877:AinR protein, Vibrio fischeri; C096878:AinS protein, Vibrio fischeri; D001426:Bacterial Proteins; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D012097:Repressor Proteins; D015534:Trans-Activators; C084289:luxL protein, Vibrio harveyi; C064778:LuxR autoinducer binding proteins; D006714:Homoserine; C030654:N-(3-oxohexanoyl)-3-aminodihydro-2(3H)-furanone; D015107:4-Butyrolactone