Format

Send to

Choose Destination
See comment in PubMed Commons below
Mol Microbiol. 2011 Jun;80(5):1381-94. doi: 10.1111/j.1365-2958.2011.07655.x. Epub 2011 Apr 20.

The Vibrio cholerae quorum sensing response is mediated by Hfq-dependent sRNA/mRNA base pairing interactions.

Author information

1
School of Biology, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA.

Abstract

Vibrio cholerae quorum sensing controls expression of four redundant sRNAs, Qrr1-4. The Qrr sRNAs are predicted to alter the translation of several mRNAs, including, hapR, which encodes a transcription factor that controls genes for virulence factors, biofilm formation, protease production and DNA uptake. Each Qrr contains a 21 nucleotide region absolutely conserved among pathogenic Vibrios, and predicted to base pair with mRNA targets, like hapR, aided by the RNA chaperone Hfq. This molecular mechanism was not experimentally tested previously, and we provide here both in vivo and in vitro evidence to validate this model. In Escherichia coli, Qrr expression repressed a HapR-GFP translational fusion, and a specific nucleotide substitution in the 21 nucleotide region eliminated HapR control, while a compensatory mutation in hapR restored it. In V. cholerae, the identical mutations also deregulated HapR-dependent gene expression and corresponding QS phenotypes by altering HapR protein levels. We calculated in vitro binding affinities of a Qrr/hapR complex and show that Hfq stabilizes complex formation. Finally, the Qrr mutation with in vivo defects also prevented Qrr/hapR binding, while the compensatory hapR mutation restored binding. These results demonstrate that the V. cholerae QS response is mediated by base pairing interactions between Qrr sRNAs and hapR mRNA.

[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley
    Loading ...
    Support Center