Functional Domains of the RhlR Transcriptional Regulator of Pseudomonas aeruginosa
AUTOR(ES)
Lamb, Janet R.
FONTE
American Society for Microbiology
RESUMO
The RhlR transcriptional regulator of Pseudomonas aeruginosa, along with its cognate autoinducer, N-butyryl homoserine lactone (C4-HSL), regulates gene expression in response to cell density. With an Escherichia coli LexA-based protein interaction system, we demonstrated that RhlR multimerized and that the degree of multimerization was dependent on the C4-HSL concentration. Studies with an E. coli lasB::lacZ lysogen demonstrated that RhlR multimerization was necessary for it to function as a transcriptional activator. Deletion analysis of RhlR indicated that the N-terminal domain of the protein is necessary for C4-HSL binding. Single amino acid substitutions in the C-terminal domain of RhlR generated mutant RhlR proteins that had the ability to bind C4-HSL and multimerize but were unable to activate lasB expression, demonstrating that the C-terminal domain is important for target gene activation. Single amino acid substitutions in both the N-terminal and C-terminal domains of RhlR demonstrated that both domains possess residues involved in multimerization. RhlR with a C-terminal deletion and an RhlR site-specific mutant form that possessed multimerization but not transcriptional activation capabilities were able to inhibit the ability of wild-type RhlR to activate rhlA expression in P. aeruginosa. We conclude that C4-HSL binding is necessary for RhlR multimerization and that RhlR functions as a multimer in P. aeruginosa.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=296234Documentos Relacionados
- Mechanism of Pseudomonas aeruginosa RhlR Transcriptional Regulation of the rhlAB Promoter
- Transcriptional Control of the Hydrogen Cyanide Biosynthetic Genes hcnABC by the Anaerobic Regulator ANR and the Quorum-Sensing Regulators LasR and RhlR in Pseudomonas aeruginosa
- The Pseudomonas aeruginosa rhlAB Operon Is Not Expressed during the Logarithmic Phase of Growth Even in the Presence of Its Activator RhlR and the Autoinducer N-Butyryl-Homoserine Lactone
- A simple alfalfa seedling infection model for Pseudomonas aeruginosa strains associated with cystic fibrosis shows AlgT (sigma-22) and RhlR contribute to pathogenesis
- The Transcriptional Regulator AlgR Is Essential for Pseudomonas aeruginosa Pathogenesis