Abstract
The CiaR/H two-component system is involved in regulating virulence and competence in Streptococcus pneumoniae. The system is known to regulate many genes, including that for high-temperature requirement A (HtrA). This gene has been implicated in the ability of the pneumococcus to colonize the nasopharynx of infant rats. We reported previously that deletion of the gene for HtrA made the pneumococcal strains much less virulent in mouse models, less able to grow at higher temperatures, and more sensitive to oxidative stress. In this report, we show that the growth phenotype as well as sensitivity to oxidative stress of Delta ciaR mutant was very similar to that of a Delta htrA mutant and that the expression of the HtrA protein was reduced in a ciaR-null mutant. Both the in vitro phenotype and the reduced virulence of Delta ciaR mutant could be restored by increasing the expression of HtrA.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptation, Physiological
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Animals
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Bacterial Proteins / physiology*
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Colony Count, Microbial
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Disease Models, Animal
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Gene Deletion
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Gene Expression Regulation, Bacterial
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Genes, Bacterial / genetics
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Genes, Bacterial / physiology
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Genetic Complementation Test
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Heat-Shock Proteins / genetics
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Heat-Shock Proteins / physiology*
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Hydrogen Peroxide / pharmacology
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Mice
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Oxidants / pharmacology
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Oxidative Stress
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Periplasmic Proteins / genetics
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Periplasmic Proteins / physiology*
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Pneumococcal Infections / microbiology
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Protein Kinases / genetics
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Protein Kinases / physiology*
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Serine Endopeptidases / genetics
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Serine Endopeptidases / physiology*
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Signal Transduction* / genetics
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Streptococcus pneumoniae / genetics*
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Streptococcus pneumoniae / growth & development
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Streptococcus pneumoniae / pathogenicity*
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Streptococcus pneumoniae / physiology
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Survival Analysis
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Temperature
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Virulence
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Virulence Factors / genetics
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Virulence Factors / metabolism*
Substances
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Bacterial Proteins
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Heat-Shock Proteins
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Oxidants
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Periplasmic Proteins
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Virulence Factors
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Hydrogen Peroxide
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Protein Kinases
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CiaR protein, Streptococcus pneumoniae
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DegP protease
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Serine Endopeptidases