title: Gene dosage compensation calibrates four regulatory RNAs to control Vibrio cholerae quorum sensing.
abstract: Quorum sensing is a mechanism of cell-to-cell communication that allows bacteria to coordinately regulate gene expression in response to changes in cell-population density. At the core of the Vibrio cholerae quorum-sensing signal transduction pathway reside four homologous small RNAs (sRNAs), named the quorum regulatory RNAs 1-4 (Qrr1-4). The four Qrr sRNAs are functionally redundant. That is, expression of any one of them is sufficient for wild-type quorum-sensing behaviour. Here, we show that the combined action of two feedback loops, one involving the sRNA-activator LuxO and one involving the sRNA-target HapR, promotes gene dosage compensation between the four qrr genes. Gene dosage compensation adjusts the total Qrr1-4 sRNA pool and provides the molecular mechanism underlying sRNA redundancy. The dosage compensation mechanism is exquisitely sensitive to small perturbations in Qrr levels. Precisely maintained Qrr levels are required to direct the proper timing and correct patterns of expression of quorum-sensing-regulated target genes.
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, USA.
authors.forename: Sine L
authors.initials: SL
authors.lastname: Svenningsen
authors.forename: Kimberly C
authors.initials: KC
authors.lastname: Tu
authors.forename: Bonnie L
authors.initials: BL
authors.lastname: Bassler
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D002138:Calibration; D004303:Dosage Compensation, Genetic; D005434:Flow Cytometry / Q000379:methods; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D010750:Phosphoproteins / Q000378:metabolism*; D053038:Quorum Sensing / Q000235:genetics*; D012313:RNA / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D014734:Vibrio cholerae / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C088907:LuxO protein, Vibrio harveyi; C117251:LuxU protein, Vibrio; D010750:Phosphoproteins; D012097:Repressor Proteins; D012313:RNA