Posttranscriptional repression of GacS/GacA-controlled genes by the RNA-binding protein RsmE acting together with RsmA in the biocontrol strain Pseudomonas fluorescens CHA0.
Détails
ID Serval
serval:BIB_87FF432C8349
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Posttranscriptional repression of GacS/GacA-controlled genes by the RNA-binding protein RsmE acting together with RsmA in the biocontrol strain Pseudomonas fluorescens CHA0.
Périodique
Journal of Bacteriology
ISSN
0021-9193[print], 0021-9193[linking]
Statut éditorial
Publié
Date de publication
2005
Volume
187
Numéro
1
Pages
276-285
Langue
anglais
Résumé
In the plant-beneficial soil bacterium Pseudomonas fluorescens CHA0, the production of biocontrol factors (antifungal secondary metabolites and exoenzymes) is controlled at a posttranscriptional level by the GacS/GacA signal transduction pathway involving RNA-binding protein RsmA as a key regulatory element. This protein is assumed to bind to the ribosome-binding site of target mRNAs and to block their translation. RsmA-mediated repression is relieved at the end of exponential growth by two GacS/GacA-controlled regulatory RNAs RsmY and RsmZ, which bind and sequester the RsmA protein. A gene (rsmE) encoding a 64-amino-acid RsmA homolog was identified and characterized in strain CHA0. Overexpression of rsmE strongly reduced the expression of target genes (hcnA, for a hydrogen cyanide synthase subunit; aprA, for the main exoprotease; and phlA, for a component of 2,4-diacetylphloroglucinol biosynthesis). Single null mutations in either rsmA or rsmE resulted in a slight increase in the expression of hcnA, aprA, and phlA. By contrast, an rsmA rsmE double mutation led to strongly increased and advanced expression of these target genes and completely suppressed a gacS mutation. Both the RsmE and RsmA levels increased with increasing cell population densities in strain CHA0; however, the amount of RsmA showed less variability during growth. Expression of rsmE was controlled positively by GacA and negatively by RsmA and RsmE. Mobility shift assays demonstrated specific binding of RsmE to RsmY and RsmZ RNAs. The transcription and stability of both regulatory RNAs were strongly reduced in the rsmA rsmE double mutant. In conclusion, RsmA and RsmE together account for maximal repression in the GacS/GacA cascade of strain CHA0.
Mots-clé
Amino Acid Sequence, Bacterial Proteins/physiology, Base Sequence, Gene Expression Regulation, Bacterial, Genes, Regulator, Molecular Sequence Data, Pest Control, Biological, Pseudomonas fluorescens/genetics, RNA-Binding Proteins/physiology, Repressor Proteins/physiology, Transcription, Genetic
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 15:00
Dernière modification de la notice
20/08/2019 15:47