TY - JOUR
T1 - CcpC, a novel regulator of the LysR family required for glucose repression of the citB gene in Bacillus subtilis
AU - Jourlin-Castelli, Cécile
AU - Mani, Nagraj
AU - Nakano, Michiko M.
AU - Sonenshein, Abraham L.
N1 - Funding Information:
This work was supported by a US Public Health Service grant (GM36718) to A. L. S. and by a grant from the National Science Foundation (MCB-9722885) to M. M. N.
PY - 2000/1/28
Y1 - 2000/1/28
N2 - Synergistic carbon catabolite repression of the Bacillus subtilis aconitase (citB) gene by glucose and a source of 2-ketoglutarate is dependent on DNA sequences located upstream of the gene. Mutations in a dyad symmetry element centered at position -66 and in a repeat of the downstream arm of the dyad symmetry at position -27 cause derepressed citB expression. In this work, a protein able to bind to a DNA fragment containing these elements was purified and identified. This protein, named CcpC (Catabolite control protein C), shares sequence similarity with members of the LysR family of transcriptional regulators. In addition to binding to the citB promoter, CcpC bound to the promoter of the citZ gene, which encodes the cell's major citrate synthase and is subject to carbon catabolite repression. In a ccpC null mutant, expression of both citB and citZ was derepressed in glucose-glutamine minimal medium, indicating that CcpC is a negative regulator of citB and citZ gene expression. DNase I footprinting experiments showed that CcpC binds to two sites within the citB promoter region, corresponding to the dyad symmetry and -27 elements. In the presence of citrate, a putative inducer, only the dyad symmetry element was fully protected by CcpC. When the dyad symmetry element was mutated, CcpC was no longer able to bind to either the dyad symmetry or -27 elements. Repression of citB and citZ gene expression during anaerobiosis also proved to be mediated by CcpC. (C) 2000 Academic Press.
AB - Synergistic carbon catabolite repression of the Bacillus subtilis aconitase (citB) gene by glucose and a source of 2-ketoglutarate is dependent on DNA sequences located upstream of the gene. Mutations in a dyad symmetry element centered at position -66 and in a repeat of the downstream arm of the dyad symmetry at position -27 cause derepressed citB expression. In this work, a protein able to bind to a DNA fragment containing these elements was purified and identified. This protein, named CcpC (Catabolite control protein C), shares sequence similarity with members of the LysR family of transcriptional regulators. In addition to binding to the citB promoter, CcpC bound to the promoter of the citZ gene, which encodes the cell's major citrate synthase and is subject to carbon catabolite repression. In a ccpC null mutant, expression of both citB and citZ was derepressed in glucose-glutamine minimal medium, indicating that CcpC is a negative regulator of citB and citZ gene expression. DNase I footprinting experiments showed that CcpC binds to two sites within the citB promoter region, corresponding to the dyad symmetry and -27 elements. In the presence of citrate, a putative inducer, only the dyad symmetry element was fully protected by CcpC. When the dyad symmetry element was mutated, CcpC was no longer able to bind to either the dyad symmetry or -27 elements. Repression of citB and citZ gene expression during anaerobiosis also proved to be mediated by CcpC. (C) 2000 Academic Press.
KW - Aconitase
KW - Bacillus subtilis
KW - Catabolite repression
KW - LysR family
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U2 - 10.1006/jmbi.1999.3420
DO - 10.1006/jmbi.1999.3420
M3 - Article
C2 - 10656796
AN - SCOPUS:0034723136
SN - 0022-2836
VL - 295
SP - 865
EP - 878
JO - Journal of molecular biology
JF - Journal of molecular biology
IS - 4
ER -