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A second operator is involved in Pseudomonas aeruginosa elastase (lasB) activation
R M Anderson1, C A Zimprich, L Rust
1Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota 58105, USA.
Journal of Bacteriology
|October 9, 1999
Summary
The Pseudomonas aeruginosa quorum-sensing system
Area of Science:
- Microbiology
- Molecular Biology
Background:
- Pseudomonas aeruginosa quorum-sensing regulates virulence factor production.
- The lasB elastase gene (lasB) is a key virulence factor controlled by the LasR quorum-sensing system.
- Optimal lasB activation involves two operator sequences, OP1 and OP2, in the promoter region.
Purpose of the Study:
- To investigate the role of the OP2 sequence in lasB gene activation.
- To determine if OP2 responds to quorum-sensing signals and the LasR protein.
- To elucidate the contribution of the autoinducer-binding domain of LasR to synergistic activation.
Main Methods:
- Utilized lasB promoter-lacZ fusion plasmids.
- Introduced sequence substitutions and insertion mutations within the promoter region.
- Analyzed gene expression changes in response to quorum-sensing components.
Main Results:
- OP1 and OP2 sequences act synergistically to mediate lasB activation.
- OP2, similar to OP1, is responsive to LasR and the autoinducer 3OC(12)-HSL.
- Synergistic activation via OP1 and OP2 does not require the autoinducer-binding domain of LasR.
Conclusions:
- The OP2 sequence is crucial for optimal lasB transcriptional activation.
- Both OP1 and OP2 are essential components of the LasR-mediated quorum-sensing regulatory network.
- LasR can mediate synergistic promoter activation independently of its direct autoinducer-binding domain, suggesting alternative regulatory mechanisms.