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Updated: Apr 24, 2026
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Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling
Published on: June 25, 2015
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A multi-tetracycline responsive induction system for gene expression in Bacillus subtilis
Keira Reich-Veillette1, Amrita E Rhoads1, Elizabeth A Libby1
1Department of Bioengineering, Northeastern University, Boston, Massachusetts, USA.
Applied and Environmental Microbiology
|April 23, 2026
Summary
Researchers developed a new tetracycline-inducible system for Bacillus subtilis, offering precise gene expression control. This robust system functions across various conditions, enhancing applications in biotechnology and microbiology.
Area of Science:
- Microbiology
- Molecular Biology
- Biotechnology
Background:
- Tightly regulated gene expression systems are crucial for microbiology research and applications.
- Bacillus subtilis, a GRAS organism, lacks robust, tunable inducible systems adaptable to diverse growth conditions.
- Existing tetracycline systems require optimization for B. subtilis's specific needs.
Purpose of the Study:
- To engineer a sensitive, tightly regulated, and homogeneous tetracycline-inducible gene expression system for Bacillus subtilis.
- To ensure the system's robustness across various media and growth conditions.
- To provide a versatile tool for precise gene expression titration in B. subtilis.
Main Methods:
- Engineered a codon-harmonized tetR repressor specific to B. subtilis.
- Developed enhanced promoter and operator architecture for improved regulation.
- Utilized a modular shuttle vector for stable, single-copy chromosomal integration.
- Tested system performance with anhydrotetracycline, chlortetracycline, and doxycycline.
Main Results:
- Achieved approximately 1,000-fold dynamic range with minimal leaky expression.
- Demonstrated effective induction using subinhibitory concentrations of multiple tetracycline derivatives.
- System showed robustness in rich media, minimal media, and on colonies.
- Successfully applied the system to titrate sgRNA expression for CRISPRi applications.
Conclusions:
- Developed a well-characterized, versatile tetracycline-inducible system for B. subtilis.
- The system offers sensitive, tightly regulated, and homogeneous gene expression.
- Enables precision titration for diverse applications including physiology studies, pathway optimization, and biotechnology.
- Demonstrated compatibility with other genetic control systems like CRISPRi.
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