DNA-binding of the Tet-transactivator curtails antigen-induced lymphocyte activation in mice
Eleonora Ottina1,2,3, Victor Peperzak4,5,6, Katia Schoeler7
1Division of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80, 6020, Innsbruck, Austria. Eleonora.Ottina@crick.ac.uk.
Abstract:
The Tet-On/Off system for conditional transgene expression constitutes state-of-the-art technology to study gene function by facilitating inducible expression in a timed and reversible manner. Several studies documented the suitability and versatility of this system to trace lymphocyte fate and to conditionally express oncogenes or silence tumour suppressor genes in vivo. Here, we show that expression of the tetracycline/doxycycline-controlled Tet-transactivator, while tolerated well during development and in immunologically unchallenged animals, impairs the expansion of antigen-stimulated T and B cells and thereby curtails adaptive immune responses in vivo. Transactivator-mediated cytotoxicity depends on DNA binding, but can be overcome by BCL2 overexpression, suggesting that apoptosis induction upon lymphocyte activation limits cellular and humoral immune responses. Our findings suggest a possible system-intrinsic biological bias of the Tet-On/Off system in vivo that will favour the outgrowth of apoptosis resistant clones, thus possibly confounding data published using such systems.
Insights
The Tet-On/Off system, used for conditional gene expression, can impair adaptive immune responses by affecting T and B cell expansion. This suggests potential bias in studies using this system, favoring apoptosis-resistant cells.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- The Tet-On/Off system enables inducible and reversible transgene expression, crucial for studying gene function.
- This system is widely used for tracing lymphocyte fate and manipulating oncogenes or tumor suppressor genes in vivo.
Purpose of the Study:
- To investigate the impact of the Tet-transactivator expression on adaptive immune responses in vivo.
- To determine if the Tet-On/Off system introduces biological bias in experimental models.
Main Methods:
- Assessed the effect of Tet-transactivator expression on antigen-stimulated T and B cell expansion.
- Investigated the mechanism of transactivator-mediated lymphocyte impairment, including DNA binding and apoptosis.
- Examined the role of BCL2 overexpression in overcoming transactivator-induced cytotoxicity.
Main Results:
- Tet-transactivator expression, while tolerated in naive animals, significantly impairs T and B cell expansion upon antigenic stimulation.
- This impairment curtails adaptive immune responses in vivo.
- Transactivator-induced cytotoxicity is DNA-binding dependent and can be rescued by BCL2 overexpression, indicating apoptosis as a key mechanism.
Conclusions:
- The Tet-On/Off system may introduce an intrinsic biological bias in vivo, favoring the outgrowth of apoptosis-resistant lymphocyte clones.
- This bias could confound data interpretation in studies utilizing the Tet-On/Off system for in vivo research.
- Researchers should consider this potential bias when designing and interpreting experiments with Tet-On/Off systems.
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