A small-RNA-mediated negative feedback loop controls quorum-sensing dynamics in Vibrio harveyi

Kimberly C. Tu, Christopher M. Waters, Sine L. Svenningsen, Bonnie Lynn Bassler

Research output: Contribution to journalArticle

61 Scopus citations

Abstract

The bioluminescent marine bacterium Vibrio harveyi uses a cell-to-cell communication process called quorum sensing (QS) to co-ordinate behaviours in response to changes in population density. QS is accomplished through the secretion and detection of extracellular signalling molecules called autoinducers. At the centre of the V. harveyi QS circuit are five small regulatory RNAs called Qrr1-5 which destabilize the mRNA of luxR, encoding LuxR, the master transcriptional regulator of QS target genes. Here we show that LuxR directly activates transcription of qrr2, qrr3 and qrr4, leading to the rapid downregulation of luxR. The LuxR-binding sites in the promoters of qrr2, qrr3 and qrr4 were identified and mutated to determine the consequences of this regulatory loop on QS dynamics. Disruption of the loop delays the transition from high to low cell density, and more significantly, decreases the cell density at which the population reaches a quorum. Our results suggest that feedback is essential for optimizing the dynamics of the transitions between individual and group behaviours.

Original languageEnglish (US)
Pages (from-to)896-907
Number of pages12
JournalMolecular Microbiology
Volume70
Issue number4
DOIs
StatePublished - Nov 2008

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology

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