Related Experiment Video
Updated: Jun 20, 2026
12:48
The Multifaceted Benefits of Protein Co-expression in Escherichia coli
Published on: February 5, 2015
One-plasmid tunable coexpression for mycobacterial protein-protein interaction studies
Yong Chang1, David Mead, Vinay Dhodda
1Biophysics Graduate Degree Program, University of Wisconsin-Madison, 433 Babcock Drive, Madison, Wisconsin 53706-1549, USA.
Protein Science : a Publication of the Protein Society
|September 18, 2009
Summary
Researchers developed a single plasmid for controlled coexpression in mycobacteria using inducible and constitutive promoters. This system enables fine-tuning protein ratios for studying complex biological systems.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Developing tools for controlled gene expression is crucial for studying gene function in mycobacteria.
- Existing methods may lack the precision needed for coexpressing multiple genes, especially for complex protein interactions.
Purpose of the Study:
- To create a versatile single-plasmid system for tunable coexpression of genes in mycobacteria.
- To optimize this system using fluorescent reporters and demonstrate its utility for expressing a multi-protein complex.
Main Methods:
- Utilized a tetracycline-inducible promoter (PtetO) and constitutive promoters (Psmyc, Pimyc, Phsp) on a single plasmid.
- Employed green fluorescent protein (GFP) and a red fluorescent inducible protein (RFIP) as reporter genes to validate promoter function and optimize coexpression.
- Coexpressed the Mycobacterium tuberculosis stearoyl-CoA Delta(9) desaturase complex (Rv3229c and Rv3230c) in Mycobacterium smegmatis.
Main Results:
- Successfully established promoter functions using GFP and RFIP reporters.
- Optimized tunable coexpression in Mycobacterium smegmatis by controlling time or inducer concentration to regulate protein ratios.
- Demonstrated successful coexpression of the two-protein fatty acid desaturase complex, showing increased catalytic activity with higher Rv3230c levels.
Conclusions:
- The developed single-plasmid system allows for finely tuned coexpression of genes in mycobacteria.
- This system is valuable for studying multicomponent protein complexes, such as the fatty acid desaturase complex.
- The tunable coexpression strategy is potentially applicable to other species with minor modifications.
Related Concept Videos
01:28Plasmids
Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...
01:29Coordination of Gene Expression Processes in Bacteria
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...