σ54-Promoter Discrimination and Regulation by ppGpp and DksA
| Autor: | Eleonore Skärfstad, Lisandro M. D. Bernardo, Victoria Shingler, Linda Johansson |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
DNA
Bacterial Transcription Genetic Molecular Sequence Data Guanosine Tetraphosphate medicine.disease_cause Biochemistry chemistry.chemical_compound Bacterial Proteins Transcription (biology) Escherichia coli medicine Promoter Regions Genetic Molecular Biology Polymerase biology Escherichia coli Proteins fungi Sigma Gene Expression Regulation Bacterial Cell Biology biology.organism_classification Pseudomonas putida Cell biology RNA Polymerase Sigma 54 chemistry biology.protein bacteria Sequence Alignment DNA Protein Binding Alarmone |
| Zdroj: | Journal of Biological Chemistry. 284:828-838 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m807707200 |
| Popis: | The sigma(54)-factor controls expression of a variety of genes in response to environmental cues. Much previous work has implicated the nucleotide alarmone ppGpp and its co-factor DksA in control of sigma(54)-dependent transcription in the gut commensal Escherichia coli, which has evolved to live under very different environmental conditions than Pseudomonas putida. Here we compared ppGpp/DksA mediated control of sigma(54)-dependent transcription in these two organisms. Our in vivo experiments employed P. putida mutants and manipulations of factors implicated in ppGpp/DksA mediated control of sigma(54)-dependent transcription in combination with a series of sigma(54)-promoters with graded affinities for sigma(54)-RNA polymerase. For in vitro analysis we used a P. putida-based reconstituted sigma(54)-transcription assay system in conjunction with DNA-binding plasmon resonance analysis of native and heterologous sigma(54)-RNA polymerase holoenzymes. In comparison with E. coli, ppGpp/DksA responsive sigma(54)-transcription in the environmentally adaptable P. putida was found to be more robust under low energy conditions that occur upon nutrient depletion. The mechanism behind this difference can be traced to reduced promoter discrimination of low affinity sigma(54)-promoters that is conferred by the strong DNA binding properties of the P. putida sigma(54)-RNA polymerase holoenzyme. |
| Databáze: | OpenAIRE |
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