CtsR is the master regulator of stress response gene expression in Oenococcus oeni.
Although many stress response genes have been characterized in Oenococcus oeni, little is known about the regulation of stress response in this malolactic bacterium. The expression of eubacterial stress genes is controlled both positively and negatively at the transcriptional level. Overall, negative regulation of heat shock genes appears to be more widespread among gram-positive bacteria. We recently identified an ortholog of the ctsR gene in O. oeni. In Bacillus subtilis, CtsR negatively regulates expression of the clp genes, which belong to the class III family of heat shock genes. The ctsR gene of O. oeni is cotranscribed with the downstream clpC gene. Sequence analysis of the O. oeni IOB 8413 (ATCC BAA-1163) genome revealed the presence of potential CtsR operator sites upstream from most of the major molecular chaperone genes, including the clp genes and the groES and dnaK operons. Using B. subtilis as a heterologous host, CtsR-dependent regulation of O. oeni molecular chaperone genes was demonstrated with transcriptional fusions. No alternative sigma factors appear to be encoded by the O. oeni IOB 8413 (ATCC BAA-1163) genome. Moreover, apart from CtsR, no known genes encoding regulators of stress response, such as HrcA, could be identified in this genome. Unlike the multiple regulatory mechanisms of stress response described in many closely related gram-positive bacteria, this is the first example where dnaK and groESL are controlled by CtsR but not by HrcA.
Grandvalet
Cosette
C
Laboratoire de Microbiologie, UMR UB/INRA 1232, ENSBANA, Université de Bourgogne, 1 Esplanade Erasme, F-21000 Dijon, France. cosette.grandvalet@u-bourgogne.fr
Coucheney
Françoise
F
Beltramo
Charlotte
C
Guzzo
Jean
J
D000251:Adenosine Triphosphatases / Q000235:genetics; D001412:Bacillus subtilis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D018833:Chaperonins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D006095:Gram-Positive Cocci / Q000235:genetics*; D006360:Heat-Shock Proteins / Q000235:genetics; D018869:Heat-Shock Response / Q000235:genetics*; D018832:Molecular Chaperones / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009876:Operon / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*
D001426:Bacterial Proteins; C087481:ClpC protein, Bacteria; C118338:CtsR protein, bacteria; D004268:DNA-Binding Proteins; C097970:GroESL protein, Bacteria; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D012097:Repressor Proteins; D000251:Adenosine Triphosphatases; D018833:Chaperonins; C115251:DnaK protein, Brevibacillus choshinensis