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CovR-controlled global regulation of gene expression in Streptococcus mutans.

Dmitriev A, Mohapatra SS, Chong P, Neely M, Biswas S, Biswas I - PLoS ONE (2011)

Bottom Line: Genes encoded by the GI TnSmu2 were found to be dramatically reduced in IBS10, while genes encoded by the GI TnSmu1 were up regulated in the mutant.The microarray data were further confirmed by real-time RT-PCR analyses.Our results indicate that CovR truly plays a significant role in the regulation of several virulence related traits in this pathogenic streptococcus.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, United States of America.

ABSTRACT
CovR/S is a two-component signal transduction system (TCS) that controls the expression of various virulence related genes in many streptococci. However, in the dental pathogen Streptococcus mutans, the response regulator CovR appears to be an orphan since the cognate sensor kinase CovS is absent. In this study, we explored the global transcriptional regulation by CovR in S. mutans. Comparison of the transcriptome profiles of the wild-type strain UA159 with its isogenic covR deleted strain IBS10 indicated that at least 128 genes (∼6.5% of the genome) were differentially regulated. Among these genes, 69 were down regulated, while 59 were up regulated in the IBS10 strain. The S. mutans CovR regulon included competence genes, virulence related genes, and genes encoded within two genomic islands (GI). Genes encoded by the GI TnSmu2 were found to be dramatically reduced in IBS10, while genes encoded by the GI TnSmu1 were up regulated in the mutant. The microarray data were further confirmed by real-time RT-PCR analyses. Furthermore, direct regulation of some of the differentially expressed genes was demonstrated by electrophoretic mobility shift assays using purified CovR protein. A proteomic study was also carried out that showed a general perturbation of protein expression in the mutant strain. Our results indicate that CovR truly plays a significant role in the regulation of several virulence related traits in this pathogenic streptococcus.

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Differential regulation of gene expression measured by quantitative real-time PCR.Bars represent either repression (A) or activation (B) in strain IBS10 (covR) relative to the wild-type strain UA159. Values are means ± standard deviations from at least three independent experiments.
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pone-0020127-g001: Differential regulation of gene expression measured by quantitative real-time PCR.Bars represent either repression (A) or activation (B) in strain IBS10 (covR) relative to the wild-type strain UA159. Values are means ± standard deviations from at least three independent experiments.

Mentions: In an attempt to validate the microarray results, quantitative real-time RT-PCR analyses were carried out. Toward this end, RNA isolated from exponentially grown cultures of UA159 and IBS10 was used for RT-PCRs with primers listed in Table S1. Nine genes that were differentially regulated according to the microarray data (Table S2) were randomly selected, and their expression was analyzed. The genes chosen were SMU.498, SMU.625, SMU.644, SMU.1001 (dprA), SMU.1004 (gftB), SMU.1396 (gbpC), SMU.1493, SMU.1983, and SMU.1988. The results are consistent with the observed microarray results (Fig. 1), and both methods strongly correlated with a coefficient of correlation value of R2 = 0.93 (data not shown). Thus, CovR indeed regulates the expression of these genes at the transcriptional level.


CovR-controlled global regulation of gene expression in Streptococcus mutans.

Dmitriev A, Mohapatra SS, Chong P, Neely M, Biswas S, Biswas I - PLoS ONE (2011)

Differential regulation of gene expression measured by quantitative real-time PCR.Bars represent either repression (A) or activation (B) in strain IBS10 (covR) relative to the wild-type strain UA159. Values are means ± standard deviations from at least three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3105014&req=5

pone-0020127-g001: Differential regulation of gene expression measured by quantitative real-time PCR.Bars represent either repression (A) or activation (B) in strain IBS10 (covR) relative to the wild-type strain UA159. Values are means ± standard deviations from at least three independent experiments.
Mentions: In an attempt to validate the microarray results, quantitative real-time RT-PCR analyses were carried out. Toward this end, RNA isolated from exponentially grown cultures of UA159 and IBS10 was used for RT-PCRs with primers listed in Table S1. Nine genes that were differentially regulated according to the microarray data (Table S2) were randomly selected, and their expression was analyzed. The genes chosen were SMU.498, SMU.625, SMU.644, SMU.1001 (dprA), SMU.1004 (gftB), SMU.1396 (gbpC), SMU.1493, SMU.1983, and SMU.1988. The results are consistent with the observed microarray results (Fig. 1), and both methods strongly correlated with a coefficient of correlation value of R2 = 0.93 (data not shown). Thus, CovR indeed regulates the expression of these genes at the transcriptional level.

Bottom Line: Genes encoded by the GI TnSmu2 were found to be dramatically reduced in IBS10, while genes encoded by the GI TnSmu1 were up regulated in the mutant.The microarray data were further confirmed by real-time RT-PCR analyses.Our results indicate that CovR truly plays a significant role in the regulation of several virulence related traits in this pathogenic streptococcus.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, United States of America.

ABSTRACT
CovR/S is a two-component signal transduction system (TCS) that controls the expression of various virulence related genes in many streptococci. However, in the dental pathogen Streptococcus mutans, the response regulator CovR appears to be an orphan since the cognate sensor kinase CovS is absent. In this study, we explored the global transcriptional regulation by CovR in S. mutans. Comparison of the transcriptome profiles of the wild-type strain UA159 with its isogenic covR deleted strain IBS10 indicated that at least 128 genes (∼6.5% of the genome) were differentially regulated. Among these genes, 69 were down regulated, while 59 were up regulated in the IBS10 strain. The S. mutans CovR regulon included competence genes, virulence related genes, and genes encoded within two genomic islands (GI). Genes encoded by the GI TnSmu2 were found to be dramatically reduced in IBS10, while genes encoded by the GI TnSmu1 were up regulated in the mutant. The microarray data were further confirmed by real-time RT-PCR analyses. Furthermore, direct regulation of some of the differentially expressed genes was demonstrated by electrophoretic mobility shift assays using purified CovR protein. A proteomic study was also carried out that showed a general perturbation of protein expression in the mutant strain. Our results indicate that CovR truly plays a significant role in the regulation of several virulence related traits in this pathogenic streptococcus.

Show MeSH
Related in: MedlinePlus