CtsR controls class III heat shock gene expression in the human pathogen Listeria monocytogenes.
Stress proteins play an important role in virulence, yet little is known about the regulation of stress response in pathogens. In the facultative intracellular pathogen Listeria monocytogenes, the Clp ATPases, including ClpC, ClpP and ClpE, are required for stress survival and intracellular growth. The first gene of the clpC operon of L. monocytogenes encodes a homologue of the Bacillus subtilis CtsR repressor of stress response genes. An L. monocytogenes ctsR-deleted mutant displayed enhanced survival under stress conditions (growth in the presence of 2% NaCl or at 42 degrees C), but its level of virulence in the mouse was not affected. The virulence of a wild-type strain constitutively expressing CtsR is significantly attenuated, presumably because of repression of the stress response. Regulation of the L. monocytogenes clpC, clpP and clpE genes was investigated using transcriptional fusions in B. subtilis as a host. The L. monocytogenes ctsR gene was placed under the control of an inducible promoter, and regulation by CtsR and heat shock was demonstrated in vivo in B. subtilis. The purified CtsR protein of L. monocytogenes binds specifically to the clpC, clpP and clpE regulatory regions, and the extent of the CtsR binding sites was defined by DNase I footprinting. Our results demonstrate that this human pathogen possesses a CtsR regulon controlling class III heat shock genes, strikingly similar to that of the saprophyte B. subtilis. This is the first description of a stress response regulatory gene in a pathogen.
Nair
S
S
Unité de Physiopathologie Moléculaire des Infections Microbiennes, INSERM U411, Faculté de Médicine Necker, 156 rue de Vaugirard, 75730 Paris Cedex 15, France.nair@necker.fr
Derré
I
I
Msadek
T
T
Gaillot
O
O
Berche
P
P
D000251:Adenosine Triphosphatases / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001412:Bacillus subtilis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D049071:Endopeptidase Clp; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics*; D018869:Heat-Shock Response / Q000235:genetics; D006801:Humans; D008089:Listeria monocytogenes / Q000235:genetics* / Q000472:pathogenicity; D008099:Liver / Q000382:microbiology; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012697:Serine Endopeptidases / Q000235:genetics; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000382:microbiology; D014774:Virulence
D001426:Bacterial Proteins; C087481:ClpC protein, Bacteria; C118338:CtsR protein, bacteria; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D012097:Repressor Proteins; D003850:Deoxyribonuclease I; D012697:Serine Endopeptidases; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C118340:ClpE protein, bacteria