Tetracycline-controlled transcriptional regulation systems: countermeasures to eliminate basal transgene leaks in Tet-based systems

Abstract

To analyze the function of any given fransgene(s) accurately in transgenic mice, and to produce credible transgenic animal models of various human diseases (precisely and realistically mimicking disease states), it is critical to be able to contiol gene expression in the animals conditionally. The ability to switch gene expression ‘on’ or ‘off’ in the restricted cells or tissue(s) at specific time(s) allows Lnprecedented flexibility for exploring gene function(s) in both the health and the disease. Pioneering work on inducible transgene expression has led to the development of a de variety of controlled gene expression systems that meet this criterion. Among them, the tetracycline-inducible systems (e.g. Tet-off and Tet-on) have been dely, frequently and successfully employed in vitro and in vivo. These systems, however, are not always tight but leaky; sometimes the leakage is significant. In some circumstances, the resulting leak is acceptable, but in others, it is more problematic. Though these systems face this disadvantage, i. e. basal transgene leakage in vitro and in vivo, several approaches, including using improved versions (e.g. rtTA2^S-M2 and rtTA2^s-S2) of rtTA, tetracycline-controlled transcriptional silencer (tTS), an ideal minimal promoter in responsive components or combinations thereof, have been developed to avoid this limitation effectively. In this review we discuss the counteimeasures available to eliminate basal transgene leakage frcrn Tet-based systems.

* Supported by National Natural Science FoLndation of China (Grant Nos. 30271177 and 39870676, National 9th Five-Year Plan Program (Grant No. 101033) Major Science and Technology Projects of Guangdong Province (Grant Nos. B602 and 2003C60101), Natural Science Foundation of Guangdong Province (Grant No. 021903) and Postdoctoral Fellowship Foundation of China (Series 29)

Keywords:

• tetracycline inducible system
• transgenic mire
• leaky expression
• transcriptional silencer

Notes

* Supported by National Natural Science FoLndation of China (Grant Nos. 30271177 and 39870676, National 9th Five-Year Plan Program (Grant No. 101033) Major Science and Technology Projects of Guangdong Province (Grant Nos. B602 and 2003C60101), Natural Science Foundation of Guangdong Province (Grant No. 021903) and Postdoctoral Fellowship Foundation of China (Series 29)