1. Dual role of CcpC protein in regulation of aconitase gene expression in Listeria monocytogenes and Bacillus subtilis.
- Author
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Mittal M, Pechter KB, Picossi S, Kim HJ, Kerstein KO, and Sonenshein AL
- Subjects
- Artificial Gene Fusion, Gene Deletion, Genes, Reporter, beta-Galactosidase biosynthesis, beta-Galactosidase genetics, Aconitate Hydratase biosynthesis, Bacillus subtilis enzymology, Bacillus subtilis genetics, Gene Expression Regulation, Bacterial, Listeria monocytogenes enzymology, Listeria monocytogenes genetics, Repressor Proteins metabolism
- Abstract
The role of the CcpC regulatory protein as a repressor of the genes encoding the tricarboxylic acid branch enzymes of the Krebs cycle (citrate synthase, citZ; aconitase, citB; and isocitrate dehydrogenase, citC) has been established for both Bacillus subtilis and Listeria monocytogenes. In addition, hyperexpression of citB-lacZ reporter constructs in an aconitase null mutant strain has been reported for B. subtilis. We show here that such hyperexpression of citB occurs in L. monocytogenes as well as in B. subtilis and that in both species the hyperexpression is unexpectedly dependent on CcpC. We propose a revision of the existing CcpC-citB regulatory scheme and suggest a mechanism of regulation in which CcpC represses citB expression at low citrate levels and activates citB expression when citrate levels are high.
- Published
- 2013
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