Title | A negative feedback loop involving small RNAs accelerates Vibrio cholerae's transition out of quorum-sensing mode. |
Publication Type | Journal Article |
Year of Publication | 2008 |
Authors | Svenningsen, SL, Waters, CM, Bassler, BL |
Journal | Genes Dev |
Volume | 22 |
Issue | 2 |
Pagination | 226-38 |
Date Published | 2008 Jan 15 |
ISSN | 0890-9369 |
Keywords | Bacterial Proteins, Base Sequence, Feedback, Molecular Sequence Data, Quorum Sensing, RNA, Bacterial, Signal Transduction, Vibrio cholerae |
Abstract | <p>Quorum sensing is a cell-to-cell communication process that allows bacteria to measure their population numbers and to synchronously alter gene expression in response to changes in cell population density. At the core of the Vibrio cholerae quorum-sensing signal transduction pathway lie four redundant small RNAs (sRNAs), named the Quorum Regulatory RNAs (Qrr1-4). Expression of qrr1-4 is cell population density-dependent due to a requirement for the quorum-sensing controlled phosphorylated response regulator LuxO-P, which is abundant only at low cell population density. When expressed, Qrr1-4 repress translation of HapR, the "master" quorum-sensing transcription factor. Here we show a negative feedback loop in which HapR activates transcription of the qrr genes, which indirectly leads to hapR repression. Efficient feedback activation of the qrr genes requires the simultaneous presence of LuxO-P (present only at low cell population density) and HapR (present only at high cell population density). For this reason, the feedback loop does not influence quorum sensing at steady-state low or high cell population density. However, LuxO-P and HapR are simultaneously present immediately following the switch from high to low cell density conditions. In this state, the HapR feedback loop dramatically accelerates V. cholerae's transition from the high to the low cell density mode.</p> |
DOI | 10.1101/gad.1629908 |
Alternate Journal | Genes Dev |
PubMed ID | 18198339 |
PubMed Central ID | PMC2192756 |
Grant List | R01 GM065859 / GM / NIGMS NIH HHS / United States 5R01 GM 065859 / GM / NIGMS NIH HHS / United States |