Individual and combined roles of the master regulators AphA and LuxR in control of the Vibrio harveyi quorum-sensing regulon.

TitleIndividual and combined roles of the master regulators AphA and LuxR in control of the Vibrio harveyi quorum-sensing regulon.
Publication TypeJournal Article
Year of Publication2013
Authorsvan Kessel, JC, Rutherford, ST, Shao, Y, Utria, AF, Bassler, BL
JournalJ Bacteriol
Volume195
Issue3
Pagination436-43
Date Published2013 Feb
ISSN1098-5530
KeywordsCell Proliferation, Escherichia coli, Gene Expression Regulation, Bacterial, Mutation, Protein Array Analysis, Quorum Sensing, Real-Time Polymerase Chain Reaction, Regulon, Repressor Proteins, Time Factors, Trans-Activators, Transcription Factors, Vibrio
Abstract

<p>Bacteria use a chemical communication process called quorum sensing to control transitions between individual and group behaviors. In the Vibrio harveyi quorum-sensing circuit, two master transcription factors, AphA and LuxR, coordinate the quorum-sensing response. Here we show that AphA regulates 167 genes, LuxR regulates 625 genes, and they coregulate 77 genes. LuxR strongly controls genes at both low cell density and high cell density, suggesting that it is the major quorum-sensing regulator. In contrast, AphA is absent at high cell density and acts to fine-tune quorum-sensing gene expression at low cell density. We examined two loci as case studies of coregulation by AphA and LuxR. First, AphA and LuxR directly regulate expression of the genes encoding the quorum-regulatory small RNAs Qrr2, Qrr3, and Qrr4, the consequence of which is a specifically timed transition between the individual and the group life-styles. Second, AphA and LuxR repress type III secretion system genes but at different times and to different extents. The consequence of this regulation is that type III secretion is restricted to a peak at mid-cell density. Thus, the asymmetric production of AphA and LuxR coupled with differences in their strengths and timing of target gene regulation generate a precise temporal pattern of gene expression.</p>

DOI10.1128/JB.01998-12
Alternate JournalJ. Bacteriol.
PubMed ID23204455
PubMed Central IDPMC3554009
Grant ListF32 AI085922 / AI / NIAID NIH HHS / United States
R01 GM065859 / GM / NIGMS NIH HHS / United States
F32AI085922 / AI / NIAID NIH HHS / United States
5R01AI054442 / AI / NIAID NIH HHS / United States
F32GM089019 / GM / NIGMS NIH HHS / United States
R01 AI054442 / AI / NIAID NIH HHS / United States
F32 GM089019 / GM / NIGMS NIH HHS / United States
P50 GM071508 / GM / NIGMS NIH HHS / United States
/ / Howard Hughes Medical Institute / United States
5R01GM065859 / GM / NIGMS NIH HHS / United States