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Published on: December 24, 2016
Purification and characterization of LasR as a DNA-binding protein
Z You1, J Fukushima, T Ishiwata
1Department of Bacteriology, Yokohama City University School of Medicine, Japan.
FEMS Microbiology Letters
|September 1, 1996
Summary
The Pseudomonas aeruginosa LasR protein binds DNA in the presence of an autoinducer, regulating elastase gene expression. This study identifies LasR as a specific DNA-binding protein crucial for bacterial virulence factor control.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Genetics
Background:
- Pseudomonas aeruginosa utilizes quorum sensing for virulence factor regulation.
- The LasR protein and autoinducer (AI) are essential for elastase gene (lasB) expression.
Purpose of the Study:
- To investigate the DNA-binding properties of the P. aeruginosa LasR protein.
- To elucidate the mechanism of LasR-mediated regulation of the lasB gene.
Main Methods:
- Overexpression and purification of LasR as a glutathione S-transferase (GST) fusion protein.
- Gel retardation assays to assess DNA binding.
- UV cross-linking analysis to confirm protein-DNA interaction.
Main Results:
- Purified GST-LasR demonstrated specific binding to operator regions 1 and 3 within the lasB upstream region.
- Binding occurred in the presence of the autoinducer.
- These regions are located 105 and 42 base pairs upstream of the lasB transcriptional start site.
Conclusions:
- LasR is a specific DNA-binding protein.
- LasR regulates lasB gene transcription in response to autoinducer presence.
- This provides a molecular basis for quorum sensing-controlled virulence in P. aeruginosa.
