The Alternative Sigma Factor SigX Controls Bacteriocin Synthesis and Competence, the Two Quorum Sensing Regulated Traits in Streptococcus mutans.
Cast your vote
You can rate an item by clicking the amount of stars they wish to award to this item.
When enough users have cast their vote on this item, the average rating will also be shown.
Your vote was cast
Thank you for your feedback
Thank you for your feedback
MetadataShow full item record
AbstractTwo small quorum sensing (QS) peptides regulate competence in S. mutans in a cell density dependent manner: XIP (sigX inducing peptide) and CSP (competence stimulating peptide). Depending on the environmental conditions isogenic S. mutans cells can split into a competent and non-competent subpopulation. The origin of this population heterogeneity has not been experimentally determined and it is unknown how the two QS systems are connected. We developed a toolbox of single and dual fluorescent reporter strains and systematically knocked out key genes of the competence signaling cascade in the reporter strain backgrounds. By following signal propagation on the single cell level we discovered that the master regulator of competence, the alternative sigma factor SigX, directly controls expression of the response regulator for bacteriocin synthesis ComE. Consequently, a SigX binding motif (cin-box) was identified in the promoter region of comE. Overexpressing the genetic components involved in competence development demonstrated that ComRS represents the origin of bimodality and determines the modality of the downstream regulators SigX and ComE. Moreover these analysis showed that there is no direct regulatory link between the two QS signaling cascades. Competence is induced through a hierarchical XIP signaling cascade, which has no regulatory input from the CSP cascade. CSP exclusively regulates bacteriocin synthesis. We suggest renaming it mutacin inducing peptide (MIP). Finally, using phosphomimetic comE mutants we show that unimodal bacteriocin production is controlled posttranslationally, thus solving the puzzling observation that in complex media competence is observed in a subpopulation only, while at the same time all cells produce bacteriocins. The control of both bacteriocin synthesis and competence through the alternative sigma-factor SigX suggests that S. mutans increases its genetic repertoire via QS controlled predation on neighboring species in its natural habitat.
CitationThe Alternative Sigma Factor SigX Controls Bacteriocin Synthesis and Competence, the Two Quorum Sensing Regulated Traits in Streptococcus mutans. 2015, 11 (7):e1005353 PLoS Genet.
AffiliationHelmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany.
The following license files are associated with this item:
- Bidirectional signaling in the competence regulatory pathway of Streptococcus mutans.
- Authors: Son M, Shields RC, Ahn SJ, Burne RA, Hagen SJ
- Issue date: 2015 Oct
- The cryptic competence pathway in Streptococcus pyogenes is controlled by a peptide pheromone.
- Authors: Mashburn-Warren L, Morrison DA, Federle MJ
- Issue date: 2012 Sep
- MecA protein acts as a negative regulator of genetic competence in Streptococcus mutans.
- Authors: Tian XL, Dong G, Liu T, Gomez ZA, Wahl A, Hols P, Li YH
- Issue date: 2013 Nov
- Intracellular Signaling by the <i>comRS</i> System in <i>Streptococcus mutans</i> Genetic Competence.
- Authors: Underhill SAM, Shields RC, Kaspar JR, Haider M, Burne RA, Hagen SJ
- Issue date: 2018 Oct 31
- Cross-feeding and interkingdom communication in dual-species biofilms of Streptococcus mutans and Candida albicans.
- Authors: Sztajer H, Szafranski SP, Tomasch J, Reck M, Nimtz M, Rohde M, Wagner-Döbler I
- Issue date: 2014 Nov