Characterization of irvR, a Novel Regulator of the irvA-Dependent Pathway Required for Genetic Competence and Dextran-Dependent Aggregation in Streptococcus mutans

Guoqing Niu; Toshinori Okinaga; Lin Zhu; Jeffrey Banas; Felicia Qi; Justin Merritt

doi:10.1128/JB.00967-08

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Characterization of irvR, a Novel Regulator of the irvA-Dependent Pathway Required for Genetic Competence and Dextran-Dependent Aggregation in Streptococcus mutans

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Characterization of irvR, a Novel Regulator of the irvA-Dependent Pathway Required for Genetic Competence and Dextran-Dependent Aggregation in Streptococcus mutans

Guoqing Niu, Toshinori Okinaga, Lin Zhu, Jeffrey Banas, Felicia Qi and Justin Merritt

Journal of bacteriology, Vol.190(21), pp.7268-7274

11/2008

DOI: 10.1128/JB.00967-08

PMCID: PMC2580701

PMID: 18757533

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Abstract

Previous studies identified irvA as a normally repressed but highly inducible transcription regulator capable of repressing mutacin I gene expression in Streptococcus mutans . In this study, we aimed to identify and characterize the regulator(s) responsible for repressing the expression of irvA . An uncharacterized open reading frame (SMU.1398) located immediately adjacent to irvA and annotated as a putative transcription repressor was identified as a likely candidate. The results of mutation studies confirmed that the expression of irvA was greatly increased in the SMU.1398 background. Mutation of SMU.1398 (“ irvR ”) abolished genetic competence and reduced the expression of the late competence genes/operons comEA , comY , and dprA without affecting the expression of the known competence regulators comC , comED , or comX . In addition, irvR was found to be a potent negative regulator of dextran-dependent aggregation (DDAG) and gbpC expression. Each of these irvR mutant phenotypes could be rescued with a double mutation of irvA or complemented by introducing a wild-type copy of irvR on a shuttle vector. These data indicate that the repression of irvA is critically dependent upon irvR and that irvA repression is essential for the development of genetic competence and the proper control of DDAG in S. mutans .

Molecular Biology of Pathogens

Details

Title: Subtitle: Characterization of irvR, a Novel Regulator of the irvA-Dependent Pathway Required for Genetic Competence and Dextran-Dependent Aggregation in Streptococcus mutans
Creators: Guoqing Niu - Department of Oral Biology, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
Toshinori Okinaga - Department of Oral Biology, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
Lin Zhu - Department of Oral Biology, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
Jeffrey Banas - Department of Oral Biology, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
Felicia Qi - Department of Oral Biology, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
Justin Merritt - Department of Oral Biology, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
Resource Type: Journal article
Publication Details: Journal of bacteriology, Vol.190(21), pp.7268-7274
DOI: 10.1128/JB.00967-08
PMID: 18757533
PMCID: PMC2580701
NLM abbreviation: J Bacteriol
ISSN: 0021-9193
eISSN: 1098-5530
Publisher: American Society for Microbiology (ASM)
Language: English
Date published: 11/2008
Academic Unit: Pediatric Dentistry; Dental Research
Record Identifier: 9984066077502771

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