Negative Feedback Loops Involving Small Regulatory RNAs Precisely Control the Vibrio harveyi Quorum-Sensing Response

Kimberly C. Tu, Tao Long, Sine L. Svenningsen, Ned S. Wingreen, Bonnie Lynn Bassler

Research output: Contribution to journalArticle

91 Scopus citations

Abstract

Quorum-sensing (QS) bacteria assess population density through secretion and detection of molecules called autoinducers (AIs). We identify and characterize two Vibrio harveyi negative feedback loops that facilitate precise transitions between low-cell-density (LCD) and high-cell-density (HCD) states. The QS central regulator LuxO autorepresses its own transcription, and the Qrr small regulatory RNAs (sRNAs) posttranscriptionally repress luxO. Disrupting feedback increases the concentration of AIs required for cells to transit from LCD to HCD QS modes. Thus, the two cooperative negative feedback loops determine the point at which V. harveyi has reached a quorum and control the range of AIs over which the transition occurs. Negative feedback regulation also constrains the range of QS output by preventing sRNA levels from becoming too high and preventing luxO mRNA levels from reaching zero. We suggest that sRNA-mediated feedback regulation is a network design feature that permits fine-tuning of gene regulation and maintenance of homeostasis.

Original languageEnglish (US)
Pages (from-to)567-579
Number of pages13
JournalMolecular Cell
Volume37
Issue number4
DOIs
StatePublished - Feb 26 2010

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

Keywords

  • MICROBIO
  • RNA

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