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Improved vectors for nisin-controlled expression in gram-positive bacteria
E M Bryan1, T Bae, M Kleerebezem
1Department of Microbiology, Institute for Advanced Studies in Biological Process Technology, Minneapolis, Minnesota 55455, USA.
Plasmid
|August 31, 2000
Summary
Researchers developed novel shuttle vectors for gram-positive bacteria and E. coli, featuring a nisin-inducible promoter. These vectors enable controlled gene expression, demonstrated by increased protein production using Enterococcus faecalis genes.
Area of Science:
- Molecular Biology
- Microbiology
- Genetic Engineering
Background:
- Shuttle vectors are essential tools for molecular biology, enabling gene manipulation across different host organisms.
- Gram-positive bacteria and Escherichia coli possess distinct genetic systems, necessitating versatile vectors for broad applicability.
- Inducible promoters offer precise control over gene expression, crucial for studying gene function and optimizing protein production.
Purpose of the Study:
- To construct and validate a novel set of shuttle vectors capable of replication in both Escherichia coli and gram-positive bacteria.
- To incorporate a nisin-inducible promoter (PnisA) and its associated two-component signaling system (NisR and NisK) for controlled gene expression.
- To demonstrate the functionality of these vectors by expressing specific genes from the Enterococcus faecalis pCF10 plasmid.
Main Methods:
- Construction of shuttle vectors containing the nisin-inducible promoter (PnisA) and the NisR/NisK two-component system.
- Cloning of Enterococcus faecalis pCF10 plasmid genes (prgX, prgY, prgZ) downstream of the PnisA promoter.
- Analysis of protein expression levels using Western blot in the presence of nisin.
Main Results:
- Successfully constructed shuttle vectors functional in both E. coli and gram-positive bacteria.
- Demonstrated nisin-inducible transcription from the PnisA promoter.
- Confirmed increased expression of cloned Enterococcus faecalis genes (prgX, prgY, prgZ) upon addition of nisin, as evidenced by Western blot analysis.
Conclusions:
- The developed shuttle vectors provide a robust platform for inducible gene expression in a dual-host system (E. coli and gram-positive bacteria).
- The nisin-inducible system (PnisA, NisR, NisK) effectively controls the expression of cloned genes.
- These vectors are valuable tools for genetic manipulation and protein production in various bacterial hosts.