Control of virulence by the two-component system CiaR/H is mediated via HtrA, a major virulence factor of Streptococcus pneumoniae.
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.
Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, G12-8QQ, United Kingdom.
Yasser Musa
YM
Ibrahim
Alison R
AR
Kerr
Jackie
J
McCluskey
Tim J
TJ
Mitchell
D000222:Adaptation, Physiological; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics / Q000502:physiology; D005816:Genetic Complementation Test; D006360:Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D033903:Periplasmic Proteins / Q000235:genetics / Q000502:physiology*; D011008:Pneumococcal Infections / Q000382:microbiology; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D012697:Serine Endopeptidases / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology; D016019:Survival Analysis; D013696:Temperature; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D016877:Oxidants; D033903:Periplasmic Proteins; D037521:Virulence Factors; D006861:Hydrogen Peroxide; D011494:Protein Kinases; C088910:CiaR protein, Streptococcus pneumoniae; C061682:DegP protease; D012697:Serine Endopeptidases