Transcriptomic Effects of Tet-On and Mifepristone-Inducible Systems in Mouse Liver

Abstract

Control of transgene expression from long-term expression vectors can be achieved with inducible and regulated promoters. The two most commonly used inducible systems employ doxycycline or mifepristone as the drug activating a silent trans-activator, which is expressed from a constitutive promoter. We evaluated the alterations provoked by constitutive expression in the liver of rtTA2 S -M2 (rtTA2; second-generation reverse tetracycline-controlled trans-activator) and GLp65, which are the trans-activators of the doxycyline-and mifepristone-inducible systems, respectively. To this end we performed transcriptomic analysis of mice expressing these trans-activators in the liver over 1 month. rtTA2 expression induced alterations in a few genes (69 gene probesets; false discovery rate [FDR], ϳ0.05), whereas GLp65 caused more numerous changes (1059 gene probe-sets, an FDR of ϳ0.05). However, only 20 and 53 of the genes from the rtTA2 and GLp65 groups, respectively, showed changes (R-fold Ն 3). Functional assignments indicate that alterations were mild and of little general significance. Few additional transcriptomic changes were observed when expressing trans-activators in the presence of inducer drugs; most were due to the drugs themselves. These results and the absence of toxicity observed in treated animals indicate that the two inducible systems are well tolerated and have little impact on the liver transcriptome profile. The milder alterations found with the use of rtTA2 suggest that this system is possibly safer for gene therapy applications. 1233

Single vector non-leaky gene expression system for Drosophila melanogaster

“…Immunogenicity 9 , global transcriptomic effects 10 , and emphysema-like changes 11 have been associated with the expression of heterologous transactivators and repressors used in mammalian systems and for gene therapy applications. Use of non-leaky endogenous IGES, analogous to the one described here, can eliminate these undesired effects 30 , 31 , 72 .…”

Recombinant adenovirus Ad-RUNrf2 reduces paraquat-induced A549 injury

“…The RU486 system is an inducible expression system used in mammalian cells. [13][14][15] Its activation and expression levels depend on the concentration of RU486 used for induction. Within a certain range, target gene expression is proportional to the RU486 dose.…”

Optogenetic dissection of neuronal circuits in zebrafish using viral gene transfer and the Tet system

“…The Tet system provides several advantages over other conditional gene expression systems in zebrafish (Esengil et al, 2007; Emelyanov and Parinov, 2008) including (1) minimal side effects on gene regulation (Reboredo et al, 2008), (2) no detectable toxicity of the modulator (Dox), (3) no interference with hormone signaling, and (4) the availability of optimized components that have been tested extensively in other species (Gossen and Bujard, 1992; Baron et al, 1997; Tang et al, 2009). Moreover, the recent development of caged Dox provides the opportunity to fine-tune the control of gene expression using optical approaches (Cambridge et al, 2009).…”