| Title: | Mechanism of competence activation by the ComRS signalling system in streptococci |
| Author(s): | Fontaine L; Goffin P; Dubout H; Delplace B; Baulard A; Lecat-Guillet N; Chambellon E; Gardan R; Hols P; |
| Address: | "Biochimie et Genetique Moleculaire Bacterienne, Institut des Sciences de la Vie, Universite catholique de Louvain, B-1348, Louvain-la-Neuve, Belgium. laetitia.fontaine@uclouvain.be" |
| ISSN/ISBN: | 1365-2958 (Electronic) 0950-382X (Linking) |
| Abstract: | "In many streptococci, competence for natural DNA transformation is regulated by the Rgg-type regulator ComR and the pheromone ComS, which is sensed intracellularly. We compared the ComRS systems of four model streptococcal species using in vitro and in silico approaches, to determine the mechanism of the ComRS-dependent regulation of competence. In all systems investigated, ComR was shown to be the proximal transcriptional activator of the expression of key competence genes. Efficient binding of ComR to DNA is strictly dependent on the presence of the pheromone (C-terminal ComS octapeptide), in contrast with other streptococcal Rgg-type regulators. The 20 bp palindromic ComR-box is the minimal genetic requirement for binding of ComR, and its sequence directly determines the expression level of genes under its control. Despite the apparent species-specific specialization of the ComR-ComS interaction, mutagenesis of ComS residues from Streptococcus thermophilus highlighted an unexpected permissiveness with respect to its biological activity. In agreement, heterologous ComS, and even primary sequence-unrelated, casein-derived octapeptides, were able to induce competence development in S. thermophilus. The lack of stringency of ComS sequence suggests that competence of a specific Streptococcus species may be modulated by other streptococci or by non-specific nutritive oligopeptides present in its environment" |
| Keywords: | "Bacterial Proteins/*metabolism Binding Sites Computational Biology *DNA Transformation Competence DNA, Bacterial/metabolism DNA-Binding Proteins/metabolism *Gene Expression Regulation, Bacterial Pheromones/metabolism Protein Binding Streptococcus/*genetic;" |
| Notes: | "MedlineFontaine, Laetitia Goffin, Philippe Dubout, Helene Delplace, Brigitte Baulard, Alain Lecat-Guillet, Nathalie Chambellon, Emilie Gardan, Rozenn Hols, Pascal eng Comparative Study Research Support, Non-U.S. Gov't England 2013/01/18 Mol Microbiol. 2013 Mar; 87(6):1113-32. doi: 10.1111/mmi.12157. Epub 2013 Feb 4" |
