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Negative control of quorum sensing by RpoN (sigma54) in Pseudomonas aeruginosa PAO1.
- Source :
-
Journal of bacteriology [J Bacteriol] 2003 Apr; Vol. 185 (7), pp. 2227-35. - Publication Year :
- 2003
-
Abstract
- In Pseudomonas aeruginosa PAO1, the expression of several virulence factors such as elastase, rhamnolipids, and hydrogen cyanide depends on quorum-sensing regulation, which involves the lasRI and rhlRI systems controlled by N-(3-oxododecanoyl)-L-homoserine lactone and N-butyryl-L-homoserine lactone, respectively, as signal molecules. In rpoN mutants lacking the transcription factor sigma(54), the expression of the lasR and lasI genes was elevated at low cell densities, whereas expression of the rhlR and rhlI genes was markedly enhanced throughout growth by comparison with the wild type and the complemented mutant strains. As a consequence, the rpoN mutants had elevated levels of both signal molecules and overexpressed the biosynthetic genes for elastase, rhamnolipids, and hydrogen cyanide. The quorum-sensing regulatory protein QscR was not involved in the negative control exerted by RpoN. By contrast, in an rpoN mutant, the expression of the gacA global regulatory gene was significantly increased during the entire growth cycle, whereas another global regulatory gene, vfr, was downregulated at high cell densities. In conclusion, it appears that GacA levels play an important role, probably indirectly, in the RpoN-dependent modulation of the quorum-sensing machinery of P. aeruginosa.
- Subjects :
- 4-Butyrolactone metabolism
Bacterial Proteins genetics
Cell Division genetics
Cyclic AMP Receptor Protein genetics
Cyclic AMP Receptor Protein metabolism
DNA-Binding Proteins genetics
DNA-Binding Proteins metabolism
DNA-Directed RNA Polymerases genetics
Gene Expression Regulation, Bacterial
Genetic Complementation Test
Ligases
Mutagenesis, Site-Directed
RNA Polymerase Sigma 54
Repressor Proteins genetics
Repressor Proteins metabolism
Sigma Factor genetics
Trans-Activators genetics
Trans-Activators metabolism
Transcription Factors genetics
Transcription Factors metabolism
4-Butyrolactone analogs & derivatives
Bacterial Proteins metabolism
DNA-Directed RNA Polymerases metabolism
Pseudomonas aeruginosa physiology
Sigma Factor metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9193
- Volume :
- 185
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Journal of bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- 12644493
- Full Text :
- https://doi.org/10.1128/JB.185.7.2227-2235.2003