Regulation of Streptococcus pneumoniae clp genes and their role in competence development and stress survival.
In vitro mariner transposon mutagenesis of Streptococcus pneumoniae chromosomal DNA was used to isolate regulatory mutants affecting expression of the comCDE operon, encoding the peptide quorum-sensing two-component signal transduction system controlling competence development. A transposon insertion leading to increased comC expression was found to lie directly upstream from the S. pneumoniae clpP gene, encoding the proteolytic subunit of the Clp ATP-dependent protease, whose expression in Bacillus subtilis is controlled by the CtsR repressor. In order to examine clp gene regulation in S. pneumoniae, a detailed analysis of the complete genome sequence was performed, indicating that there are five likely CtsR-binding sites located upstream from the clpE, clpP, and clpL genes and the ctsR-clpC and groESL operons. The S. pneumoniae ctsR gene was cloned under the control of an inducible promoter and used to demonstrate regulation of the S. pneumoniae clpP and clpE genes and the clpC and groESL operons by using B. subtilis as a heterologous host. The CtsR protein of S. pneumoniae was purified and shown to bind specifically to the clpP, clpC, clpE, and groESL regulatory regions. S. pneumoniae Delta ctsR, Delta clpP, Delta clpC, and Delta clpE mutants were constructed by gene deletion/replacement. ClpP was shown to act as a negative regulator, preventing competence gene expression under inappropriate conditions. Phenotypic analyses also indicated that ClpP and ClpE are both required for thermotolerance. Contrary to a previous report, we found that ClpC does not play a major role in competence development, autolysis, pneumolysin production, or growth at high temperature of S. pneumoniae.
Chastanet
A
A
Unité de Biochimie Microbienne, Institut Pasteur, URA 2172 du Centre National de la Recherche Scientifique, 75724 Paris Cedex 15, France.
Prudhomme
M
M
Claverys
J P
JP
Msadek
T
T
D000251:Adenosine Triphosphatases / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D018833:Chaperonins / Q000378:metabolism; D049071:Endopeptidase Clp; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics*; D018869:Heat-Shock Response / Q000235:genetics; D008969:Molecular Sequence Data; D009876:Operon; D011485:Protein Binding; D018085:Regulon; D012097:Repressor Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics*; D013296:Streptococcus pneumoniae / Q000502:physiology*; D014169:Transformation, Bacterial / Q000235:genetics
D001426:Bacterial Proteins; C087481:ClpC protein, Bacteria; C118338:CtsR protein, bacteria; C097970:GroESL protein, Bacteria; D006360:Heat-Shock Proteins; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; D018833:Chaperonins; C118340:ClpE protein, bacteria