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J Bacteriol

Title:		Regulation of bacteriocin production in Streptococcus mutans by the quorum-sensing system required for development of genetic competence
Author(s):		van der Ploeg JR;
Address:		"Institute for Oral Biology, Center for Dental-, Oral Medicine and Maxillofacial Surgery, University of Zurich, Plattenstrasse 11, CH-8032, Zurich, Switzerland. jvdploeg@zzmk.unizh.ch"
Journal Title:		J Bacteriol
Year:		2005
Volume:		187
Issue:		12
Page Number:		3980 - 3989
DOI:		10.1128/JB.187.12.3980-3989.2005
ISSN/ISBN:		0021-9193 (Print) 1098-5530 (Electronic) 0021-9193 (Linking)
Abstract:		"In Streptococcus mutans, competence for genetic transformation and biofilm formation are dependent on the two-component signal transduction system ComDE together with the inducer peptide pheromone competence-stimulating peptide (CSP) (encoded by comC). Here, it is shown that the same system is also required for expression of the nlmAB genes, which encode a two-peptide nonlantibiotic bacteriocin. Expression from a transcriptional nlmAB'-lacZ fusion was highest at high cell density and was increased up to 60-fold following addition of CSP, but it was abolished when the comDE genes were interrupted. Two more genes, encoding another putative bacteriocin and a putative bacteriocin immunity protein, were also regulated by this system. The regions upstream of these genes and of two further putative bacteriocin-encoding genes and a gene encoding a putative bacteriocin immunity protein contained a conserved 9-bp repeat element just upstream of the transcription start, which suggests that expression of these genes is also dependent on the ComCDE regulatory system. Mutations in the repeat element of the nlmAB promoter region led to a decrease in CSP-dependent expression of nlmAB'-lacZ. In agreement with these results, a comDE mutant and mutants unable to synthesize or export CSP did not produce bacteriocins. It is speculated that, at high cell density, bacteriocin production is induced to liberate DNA from competing streptococci"
Keywords:		"Amino Acid Sequence Bacterial Proteins/genetics/*physiology Bacteriocins/*biosynthesis/genetics Base Sequence Chromosome Mapping Chromosomes, Bacterial *Gene Expression Regulation, Bacterial Mutation Recombinant Fusion Proteins/biosynthesis Sequence Align;"
Notes:		"Medlinevan der Ploeg, Jan R eng Research Support, Non-U.S. Gov't 2005/06/07 J Bacteriol. 2005 Jun; 187(12):3980-9. doi: 10.1128/JB.187.12.3980-3989.2005"