A versatile nonviral vector system for tetracycline-dependent one-step conditional induction of transgene expression

Area of Science:

• Molecular Biology
• Gene Expression Systems
• Biotechnology

Background:

• Conventional methods for establishing stable transgene expression require multiple clonal selection rounds.
• Developing inducible systems, particularly tetracycline (Tet)-inducible systems, can be complex and time-consuming.
• Efficient and rapid generation of stable mammalian cell lines with controllable gene expression is crucial for research and therapeutic applications.

Purpose of the Study:

• To develop a novel, self-contained, nonviral vector system for rapid generation of tetracycline (Tet)-inducible transgene expression in mammalian cell lines.
• To enable one-step targeted genomic integration and conditional transgene expression, bypassing extensive clonal selection.
• To demonstrate the system's efficacy in achieving stable, robust, and controllable protein expression.

Main Methods:

• Construction of a multicomplementary DNA (cDNA) expression vector containing Tet-inducible promoter and Tet repressor units.
• Utilizing phiC31 integrase-mediated chromosomal integration for one-step targeted genomic insertion.
• Testing the system in five different mammalian cell lines and evaluating protein expression levels and inducibility with doxycycline.

Main Results:

• Generated stable cell clones exhibiting robust transgene expression with high induction rates upon doxycycline addition.
• Achieved rapid protein production from low background levels, which returned to baseline within days of inducer withdrawal.
• Successfully demonstrated c-Src-induced cell transformation and subsequent cell therapy in cultured fibroblast cells using the developed system.

Conclusions:

• The novel nonviral vector system facilitates rapid development of Tet-inducible transgene expression in mammalian cells.
• The system provides stable, controllable gene expression with efficient integration, simplifying cell line generation.
• This technology holds potential for advancing research in cell transformation, cancer cell therapy, and protein production applications.