The CytR repressor antagonizes cyclic AMP-cyclic AMP receptor protein activation of the deoCp2 promoter of Escherichia coli K-12

TY - JOUR

T1 - The CytR repressor antagonizes cyclic AMP-cyclic AMP receptor protein activation of the deoCp2 promoter of Escherichia coli K-12

AU - Søgaard-Andersen, Lotte

AU - Martinussen, J

AU - Møllegaard, N E

AU - Douthwaite, S R

AU - Valentin-Hansen, P

N1 - Keywords: Base Sequence; Chromosome Deletion; Cyclic AMP; DNA, Bacterial; Escherichia coli; Escherichia coli Proteins; Molecular Sequence Data; Mutation; Oligonucleotide Probes; Plasmids; Promoter Regions, Genetic; Receptors, Cyclic AMP; Recombinant Fusion Proteins; Repressor Proteins; Restriction Mapping; beta-Galactosidase

PY - 1990

Y1 - 1990

N2 - We have investigated the regulation of the Escherichia coli deoCp2 promoter by the CytR repressor and the cyclic AMP (cAMP) receptor protein (CRP) complexed to cAMP. Promoter regions controlled by these two proteins characteristically contain tandem cAMP-CRP binding sites. Here we show that (i) CytR selectively regulated cAMP-CRP-dependent initiations, although transcription started from the same site in deoCp2 in the absence or presence of cAMP-CRP; (ii) deletion of the uppermost cAMP-CRP target (CRP-2) resulted in loss of CytR regulation, but had only a minor effect on positive control by the cAMP-CRP complex; (iii) introduction of point mutations in either CRP target resulted in loss of CytR regulation; and (iv) regulation by CytR of deletion mutants lacking CRP-2 could be specifically reestablished by increasing the intracellular concentration of CytR. These findings indicate that both CRP targets are required for efficient CytR repression of deoCp2. Models for the action of CytR are discussed in light of these findings.

AB - We have investigated the regulation of the Escherichia coli deoCp2 promoter by the CytR repressor and the cyclic AMP (cAMP) receptor protein (CRP) complexed to cAMP. Promoter regions controlled by these two proteins characteristically contain tandem cAMP-CRP binding sites. Here we show that (i) CytR selectively regulated cAMP-CRP-dependent initiations, although transcription started from the same site in deoCp2 in the absence or presence of cAMP-CRP; (ii) deletion of the uppermost cAMP-CRP target (CRP-2) resulted in loss of CytR regulation, but had only a minor effect on positive control by the cAMP-CRP complex; (iii) introduction of point mutations in either CRP target resulted in loss of CytR regulation; and (iv) regulation by CytR of deletion mutants lacking CRP-2 could be specifically reestablished by increasing the intracellular concentration of CytR. These findings indicate that both CRP targets are required for efficient CytR repression of deoCp2. Models for the action of CytR are discussed in light of these findings.

M3 - Journal article

C2 - 2170326

SN - 0021-9193

VL - 172

SP - 5706

EP - 5713

JO - Journal of Bacteriology

JF - Journal of Bacteriology

IS - 10

ER -