Regulatory RNA as mediator in GacA/RsmA-dependent global control of exoproduct formation in Pseudomonas fluorescens CHA0.

Détails

ID Serval
serval:BIB_88B7D596164E
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Regulatory RNA as mediator in GacA/RsmA-dependent global control of exoproduct formation in Pseudomonas fluorescens CHA0.
Périodique
Journal of Bacteriology
Auteur⸱e⸱s
Heeb S., Blumer C., Haas D.
ISSN
0021-9193 (Print)
ISSN-L
0021-9193
Statut éditorial
Publié
Date de publication
2002
Volume
184
Numéro
4
Pages
1046-1056
Langue
anglais
Résumé
In Pseudomonas fluorescens CHA0, an antagonist of root-pathogenic fungi, the GacS/GacA two-component system tightly controls the expression of antifungal secondary metabolites and exoenzymes at a posttranscriptional level, involving the RNA-binding protein and global regulator of secondary metabolism RsmA. This protein was purified from P. fluorescens, and RNA bound to it was converted to cDNA, which served as a probe to isolate the corresponding chromosomal locus, rsmZ. This gene encoded a regulatory RNA of 127 nucleotides and a truncated form lacking 35 nucleotides at the 3' end. Expression of rsmZ depended on GacA, increased with increasing population density, and was stimulated by the addition of a solvent-extractable extracellular signal produced by strain CHA0 at the end of exponential growth. This signal appeared to be unrelated to N-acyl-homoserine lactones. A conserved upstream element in the rsmZ promoter, but not the stress sigma factor RpoS, was involved in rsmZ expression. Overexpression of rsmZ effectively suppressed the negative effect of gacS and gacA mutations on target genes, i.e., hcnA (for hydrogen cyanide synthase) and aprA (for the major exoprotease). Mutational inactivation of rsmZ resulted in reduced expression of these target genes in the presence of added signal. Overexpression of rsmA had a similar, albeit stronger negative effect. These results support a model in which GacA upregulates the expression of regulatory RNAs, such as RsmZ of strain CHA0, in response to a bacterial signal. By a titration effect, RsmZ may then alleviate the repressing activity of RsmA on the expression of target mRNAs.
Mots-clé
4-Butyrolactone/analogs & derivatives, 4-Butyrolactone/metabolism, Amino Acid Sequence, Bacterial Proteins/genetics, Bacterial Proteins/metabolism, Base Sequence, Chromosome Mapping, Chromosomes, Bacterial, DNA, Bacterial, Exopeptidases/genetics, Genes, Bacterial, Genes, Regulator, Molecular Sequence Data, Multienzyme Complexes/genetics, Mutagenesis, Nucleic Acid Conformation, Oxidoreductases/genetics, Oxidoreductases Acting on CH-NH2 Group Donors, Pseudomonas fluorescens/genetics, Pseudomonas fluorescens/metabolism, RNA, Bacterial/genetics, RNA-Binding Proteins/genetics, RNA-Binding Proteins/metabolism, Regulatory Sequences, Nucleic Acid, Repressor Proteins/genetics, Repressor Proteins/metabolism, Sigma Factor/metabolism, Transcription Factors/genetics, Transcription Factors/metabolism
Pubmed
Web of science
Open Access
Oui
Création de la notice
25/01/2008 17:01
Dernière modification de la notice
20/08/2019 14:47
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