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Published on: June 25, 2015
A novel strategy for regulated expression of a cytotoxic gene
Y M Bi1, S J Rothstein, A G Wildeman
1Department of Molecular Biology and Genetics, University of Guelph, Ontario, Canada N1G 2W1.
Abstract:
The tetracycline (Tet) transactivator system is a powerful promoter system to control gene expression. However, expression of a cytotoxic gene in this system has been limited due to the lethal effect caused by low levels of basal expression of the toxic gene. In this report, we describe a novel strategy to express a toxic gene using the Tet system. The barstar gene is placed downstream of a minimal promoter and the barnase gene downstream of the tetracycline responsive element minimal promoter. When barnase is expressed at a basal level, its toxicity in human cell culture is offset by the similar basal level expression of barstar. However, when the barnase expression is induced with the transactivator protein, its overproduction leads to cell death. Therefore, this strategy allows cytotoxicity to be effectively regulated by tetracycline.
Insights
This study presents a new method for controlling toxic gene expression using the tetracycline (Tet) transactivator system. By balancing barnase and barstar gene expression, researchers can safely induce cell death with tetracycline.
Area of Science:
- Molecular Biology
- Gene Expression Regulation
- Cellular Toxicology
Background:
- The tetracycline (Tet) transactivator system is widely used for inducible gene expression.
- Controlling cytotoxic gene expression with the Tet system is challenging due to basal expression toxicity.
Purpose of the Study:
- To develop a novel strategy for tightly regulating toxic gene expression using the Tet system.
- To enable controlled induction of cell death in human cell cultures.
Main Methods:
- Co-expression of barnase (toxic gene) and barstar (inhibitory protein) under Tet-inducible control.
- Placing the barstar gene downstream of a minimal promoter and barnase downstream of a Tet-responsive minimal promoter.
- Utilizing basal expression of barnase and barstar to offset toxicity, with induced barnase expression leading to cell death.
Main Results:
- Basal expression of barnase and barstar maintained cell viability.
- Tetracycline induction of barnase resulted in significant cell death.
- Demonstrated effective regulation of cytotoxicity via tetracycline administration.
Conclusions:
- The developed Tet-inducible system allows for safe handling and precise control of toxic gene expression.
- This strategy overcomes limitations of basal expression toxicity in Tet-controlled systems.
- Offers a valuable tool for applications requiring regulated cell death, such as cancer research or gene therapy.
