Related Experiment Video
Updated: Jul 30, 2025
08:51
Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling
Published on: June 25, 2015
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Development of a Tetracycline-Inducible System for Conditional Gene Expression in Lactococcus lactis and
Sofia Markakiou1,2, Ana Rute Neves1, Ahmad A Zeidan1
1R&D Department, Chr. Hansen A/S, Hørsholm, Denmark.
Microbiology Spectrum
|May 16, 2023
Summary
We developed a controllable gene expression system for key industrial bacteria, Lactococcus lactis and Streptococcus thermophilus, enabling precise study of essential genes and protein production.
Area of Science:
- Microbiology
- Molecular Biology
- Biotechnology
Background:
- Inducible gene expression systems are crucial for studying gene function and constructing protein overexpression hosts.
- Controllable expression is vital for essential, toxic, or dose-sensitive genes in bacteria.
- Lactococcus lactis and Streptococcus thermophilus are industrially significant lactic acid bacteria used in food fermentation and as hosts for heterologous protein production.
Purpose of the Study:
- To implement and optimize a tetracycline-inducible gene expression system in Lactococcus lactis and Streptococcus thermophilus.
- To achieve tight, controllable, and inducer-responsive gene expression in these industrially relevant bacterial species.
- To expand the molecular genetic toolbox for lactic acid bacteria, facilitating physiological studies and biotechnological applications.
Main Methods:
- Implementation of the tetracycline-inducible expression system using a fluorescent reporter gene.
- Optimization of repression levels and TetR expression via random mutagenesis in Lactococcus lactis.
- Chromosomal integration in Streptococcus thermophilus using markerless mutagenesis and a novel DNA fragment assembly tool.
Main Results:
- Successful optimization of anhydrotetracycline-inducible gene expression in both Lactococcus lactis and Streptococcus thermophilus.
- Achieved plasmid-based, tight, and inducer-responsive gene expression in Lactococcus lactis.
- Demonstrated chromosomal integration and functionality of the inducible system in Streptococcus thermophilus.
Conclusions:
- The developed inducible expression system offers advantages for lactic acid bacteria research and biotechnology.
- Further advancements in genetic engineering techniques are needed for broader application in species like Streptococcus thermophilus.
- This work enhances the molecular capabilities of Lactococcus lactis and Streptococcus thermophilus for future research and industrial use.
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