Catabolite repression of the citST two-component system in Bacillus subtilis.
In Bacillus subtilis, expression of the citrate transporter CitM is under strict control. Transcription of the citM gene is induced by citrate in the medium mediated by the CitS-CitT two-component system and repressed by rapidly degraded carbon sources mediated by carbon catabolite repression (CCR). In this study, we demonstrate that citST genes are part of a bicistronic operon. The promoter region was localized in a stretch of 58 base pairs upstream of the citS gene by deletion experiments. Transcription of the operon was repressed in the presence of glucose by the general transcription factor CcpA. A distal consensus cre site in the citS-coding sequence was implicated in the mechanism of repression. Furthermore, this repression was relieved in Bacillus subtilis mutants deficient in CcpA or Hpr/Crh, components essential to CCR. Thus, we demonstrate that CCR represses the expression of the citST operon, which is responsible for the induction of citM, through the cre site located 1326 bp from transcriptional start site of citST.
Repizo
Guillermo D
GD
Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
Blancato
Víctor S
VS
Sender
Pablo D
PD
Lolkema
Juke
J
Magni
Christian
C
D001412:Bacillus subtilis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002244:Carbon / Q000378:metabolism / Q000494:pharmacology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002951:Citrates / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009876:Operon; D027361:Organic Anion Transporters / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D027981:Symporters; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D002352:Carrier Proteins; C102671:CitM protein, Bacillus subtilis; C086246:CitS protein, bacteria; C113956:CitT protein, E coli; D002951:Citrates; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D027361:Organic Anion Transporters; D012097:Repressor Proteins; D027981:Symporters; C069286:catabolite control proteins, bacteria; D002244:Carbon; D005947:Glucose