Microarray-based identification of htrA, a Streptococcus pneumoniae gene that is regulated by the CiaRH two-component system and contributes to nasopharyngeal colonization.
Nasopharyngeal carriage is the reservoir from which most disease with Streptococcus pneumoniae arises. Survival as a commensal in this environment is likely to require a set of adaptations distinct from those needed to cause disease, some of which may be mediated by two-component signal transduction systems (TCSTS). We examined the contributions of nine pneumococcal TCSTS to the process of nasopharyngeal colonization by using an infant rat model. Whereas deletions in all but one of these systems have been associated previously with a high degree of attenuation in a murine model of pneumonia, only the CiaRH system was necessary for efficient carriage. Transcriptional analysis by using microarray hybridization identified a locus consisting of two adjacent genes, htrA and spoJ, that was specifically and strongly downregulated in a DeltaciaRH-null mutant. A S. pneumoniae strain lacking the htrA gene encoding a putative serine protease, but not one lacking spoJ, showed decreased fitness in a competitive model of colonization, a finding consistent with this gene mediating a portion of the carriage deficit observed with the DeltaciaRH strain.
Department of Pediatrics, Children's Hospital of Philadelphia, Pennsylvania 19104, USA.
M E
ME
Sebert
L M
LM
Palmer
M
M
Rosenberg
J N
JN
Weiser
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D004195:Disease Models, Animal; D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins; D000071677:Histidine Kinase; D009305:Nasopharynx / Q000382:microbiology; D020411:Oligonucleotide Array Sequence Analysis; D033903:Periplasmic Proteins; D011008:Pneumococcal Infections / Q000382:microbiology; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012697:Serine Endopeptidases / Q000235:genetics*; D015398:Signal Transduction; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D033903:Periplasmic Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase; C088910:CiaR protein, Streptococcus pneumoniae; C061682:DegP protease; D012697:Serine Endopeptidases