In vivo effect of DNA relaxation on the transcription of gene rpoH in Escherichia coli.

  title={In vivo effect of DNA relaxation on the transcription of gene rpoH in Escherichia coli.},
  author={F L{\'o}pez-S{\'a}nchez and Jes{\'u}s Ram{\'i}rez-Santos and M. Carmen G{\'o}mez‐Eichelmann},
  journal={Biochimica et biophysica acta},
  volume={1353 1},
The in vivo effect of Novobiocin, a gyrase inhibitor, on the transcription of gene rpoH which codes for sigma32, the main positive regulator of the heat-shock response, was studied. Novobiocin induced a three-fold increase and a slight decrease in the activity of the rpoH promoters P1 and P4, respectively. The Novobiocin-induced increase in the activity of promoter P1 correlates with an increase in the amount of proteins sigma32 and DnaK. These results suggest that the increase in expression of… Expand
Analysis of the regulatory region of the heat-shock gene rpoH of Escherichia coli strains isolated from non-human hosts.
The regulatory region of the gene for sigma32, rpoH, of Escherichia coli strains isolated from non-human hosts and different geographic regions, was sequenced and compared with that of E. coli K12.Expand
DNA topology and the thermal stress response, a tale from mesophiles and hyperthermophiles.
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Models for the regulation of the cytoplasmic and periplasmic response to heat in E. coli are presented and it is shown that these factors, under non-stress and stress conditions, depends upon negative and positive regulatory mechanisms acting at different levels. Expand
Regulation of the heat-shock response.
Current models of both heat induction and the chaperone-mediated feedback control of the sigma32 regulon in Escherichia coli have been further substantiated, and the extent of conservation amongExpand
Effect of anaerobic and stationary phase growth conditions on the heat shock and oxidative stress responses in Escherichia coli K-12
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Topoisomerase function during bacterial responses to environmental challenge.
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A novel sigma factor is involved in expression of the rpoH gene of Escherichia coli
The isolation of a novel sigma factor of about 24 kilodaltons that allows core RNA polymerase to transcribe preferentially from one of these promoters, rpoH3p, suggests that induction of heat shock proteins by the stringent response is not mediated by increased transcription of the rPOH gene. Expand
Topoisomerase activity during the heat shock response in Escherichia coli K-12
The results suggest that gyrase and proteins synthesized during heat shock are responsible for the changes seen in plasmid supercoiling in cells treated with chloramphenicol and novobiocin. Expand
Transcriptional regulation of the heat shock regulatory gene rpoH in Escherichia coli: involvement of a novel catabolite-sensitive promoter
Analysis of rpoH mRNAs by S1 nuclease protection experiments led to a novel promoter, designated P5, that is regulated by cAMP and the cAMP receptor protein that is increased by the addition of ethanol to the growth medium; however, the increase is greater in the presence of glucose than in its absence. Expand
Regulation of the promoters and transcripts of rpoH, the Escherichia coli heat shock regulatory gene.
Using S1 mapping, promoter cloning, and in vitro transcription, the promoters and the terminator for the rpoH transcription unit are identified and it is shown that there is post-transcriptional control of the level of rPOH mRNA and presumably of sigma 32. Expand
Heat shock regulatory gene rpoH mRNA level increases after heat shock in Escherichia coli
It is shown that rpoH transcript levels increased after heat shock and that the magnitude of the increase in the level of mRNA was correlated with the severity of the temperature shift. Expand
dnaA protein regulates transcriptions of the rpoH gene of Escherichia coli.
The binding of dnaA protein to the rpoH promoter region resulted in transcriptional repression from two of the three promoters of the rPoH gene in vitro and in vivo, indicating that dnA protein regulates rpoh transcription to influence the expression of genes under rpo H control. Expand
Regulation of the heat-shock response in bacteria.
A clue to further understanding of early regulatory events came from recent analysis of translational induction and subsequent shut-off of sigma 32 synthesis, which indicates that a distinct segment of s Sigma 32 polypeptide further downstream is involved in the DnaK/DnaJ-mediated Shut-off and destabilization ofSigma 32 that may be mutually interconnected. Expand
Isolation and characterization of Escherichia coli mutants that lack the heat shock sigma factor sigma 32
It is concluded that sigma 32 is required for cell growth at temperatures above 20 degrees C and is requiredFor transcription from the heat shock promoters and several heat shock proteins are synthesized in the absence of s Sigma 32, indicating that there are additional mechanisms controlling the synthesis of some heat shock genes. Expand
The heat shock response of E. coli is regulated by changes in the concentration of σ32
The results indicate that σ32 is directly responsible for regulation of the heat shock response, and measured the amount of ρ32 before and after shift to high temperature and found that it increased transiently during heat shock as a result of changes in σ 32 synthesis and stability. Expand
rpoE, the gene encoding the second heat‐shock sigma factor, sigma E, in Escherichia coli.
It is suggested that a gene encoding a negative regulator of sigma E activity is located immediately downstream of rpoE and may function as the target of the E s Sigma E inducing signal. Expand