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LuxR-type quorum-sensing regulators that are detached from common scents
Ching-Sung Tsai1, Stephen C Winans
1Department of Microbiology, Cornell University, Ithaca, NY 14853, USA.
Molecular Microbiology
|July 14, 2010
Summary
Certain LuxR-type proteins regulate bacterial transcription without N-acylhomoserine lactones (AHLs), but are inhibited by them. This suggests a dual regulatory mechanism for these important bacterial signaling molecules.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- LuxR-type proteins are key transcriptional regulators in bacteria.
- Their activity is typically controlled by N-acylhomoserine lactones (AHLs), which are bacterial pheromones.
- Most LuxR proteins require AHLs for proper folding, stability, and DNA binding.
Purpose of the Study:
- To investigate LuxR-type proteins that function independently of AHLs.
- To understand the antagonistic role of AHLs in specific LuxR-protein interactions.
- To explore potential co-regulation mechanisms between LuxR receptors and AHL synthase genes.
Main Methods:
- Comparative analysis of LuxR-family protein structures and functions.
- In vitro studies of protein-DNA complex formation and disruption by AHLs.
- Examination of gene organization and potential co-transcription of LuxR and AHL synthase genes.
Main Results:
- A subset of LuxR-type proteins can fold, dimerize, bind DNA, and regulate transcription without AHLs.
- These AHL-independent proteins are antagonized by their cognate AHLs.
- AHLs disrupt the binding of some LuxR proteins to their DNA targets in vitro.
- Genes for these receptors and their AHL synthases show overlapping 3' ends.
Conclusions:
- Some LuxR-type proteins exhibit AHL-antagonized activity, diverging from the typical AHL-dependent model.
- AHLs can act as antagonists, not just activators, for certain LuxR-type transcriptional regulators.
- Gene structure suggests potential co-regulation at the mRNA level, adding another layer of antagonism.
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