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- Title
The σ-factor FliA, ppGpp and DksA coordinate transcriptional control of the aer2 gene of Pseudomonas putida.
- Authors
Österberg, Sofia; Skärfstad, Eleonore; Shingler, Victoria
- Abstract
Here the σ-factor requirement for transcription of three similar, but differentially regulated, aer genes of Pseudomonas putida KT2440 is investigated. Previous work has shown that the three Aer proteins, like chemoreceptors, colocalize to a single pole in a CheA-dependent manner. Lack of Aer2 – the most abundant of these three proteins – mediates defects in metabolism-dependent taxis and aerotaxis, while lack of Aer1 or Aer3 has no apparent phenotype. We show, using wild-type and mutant P. putida derivatives combined with P. putida reconstituted FliA- (σ28) and σ70-dependent in vitro transcription assays, that transcription of aer2 is coupled to motility through the flagella σ-factor FliA, while σ70 is responsible for transcription of aer1 and aer3. By comparing activities of the wild-type and mutant forms of the aer2 promoter, we present evidence (i) that transcription from FliA-dependent P aer2 is enhanced by changes towards the Escherichia coli consensus for FliA promoters rather than towards that of P. putida, (ii) that the nature of the AT-rich upstream region is important for both output and σ70 discrimination of this promoter, and (iii) that P aer2 output is directly stimulated by the bacterial alarmone ppGpp and its cofactor DksA.
- Subjects
PSEUDOMONAS; BACTERIAL genetics; ESCHERICHIA coli; GENETIC transcription; TRANSCRIPTION factors; GENETIC regulation; GENETIC mutation
- Publication
Environmental Microbiology, 2010, Vol 12, Issue 6, p1439
- ISSN
1462-2912
- Publication type
Article
- DOI
10.1111/j.1462-2920.2009.02139.x