Involvement of two distinct catabolite-responsive elements in catabolite repression of the Bacillus subtilis myo-inositol (iol) operon.
The Bacillus subtilis inositol operon (iolABCDEFGHIJ) is involved in myo-inositol catabolism. Glucose repression of the iol operon induced by inositol is exerted through catabolite repression mediated by CcpA and the iol induction system mediated by IolR. In this study, we identified two iol catabolite-responsive elements (cre's), to which CcpA complexed with P-Ser-HPr or P-Ser-Crh probably binds. One is located in iolB (cre-iolB, nucleotides +2397 to +2411; +1 is the transcription initiation nucleotide), which was the only cre-iol found in the previous cre search of the B. subtilis genome using a query sequence of WTGNAANCGNWNNCW (W stands for A or T, and N stands for any base). Deletion and base substitution analysis of the iol region indicated that cre-iolB functions even if it is located far downstream of the iol promoter. Further deletion and base substitution analysis revealed another cre located between the iol promoter and the iolA gene (cre-iiolA, nucleotides +86 to +100); the prefix "i" indicates a location in the intergenic region. Both cre-iiolA and cre-iolB appeared to be recognized to almost the same extent by CcpA complexed with either P-Ser-HPr or P-Ser-Crh. Sequence alignment of the six known cre's, including cre-iiolA, which were not revealed in the previous cre search, exhibited another consensus sequence of WTGAAARCGYTTWWN (R stands for A or G, and Y stands for C or T); the right two thymines (TT) were found to be essential for the function of cre-iiolA by means of base substitution analysis. A cre search with this query sequence led to the finding of 14 additional putative cre's.
Miwa
Y
Y
Department of Marine Biotechnology, Faculty of Engineering, Fukuyama University, Fukuyama 729-0292, Japan.
Fujita
Y
Y
D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005947:Glucose / Q000494:pharmacology; D007294:Inositol / Q000378:metabolism*; D009876:Operon; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D020218:Response Elements / Q000235:genetics*; D013401:Sugar Alcohol Dehydrogenases / Q000096:biosynthesis
D001426:Bacterial Proteins; C118042:Crh protein, Bacillus subtilis; D004268:DNA-Binding Proteins; D010750:Phosphoproteins; D012097:Repressor Proteins; C069286:catabolite control proteins, bacteria; D007294:Inositol; D013401:Sugar Alcohol Dehydrogenases; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; D005947:Glucose