Clontech’s Tet-Express Inducible Expression Systems are a faster, simpler adaptation of our powerful, tightly-regulated Tet-On/Tet-Off expression systems. Unlike Tet-On/Tet-Off, the Tet-Express system requires only a single vector, the Tet-Express transducible protein, and a doxycycline-free protocol. To induce expression, simply apply a few microliters of Tet-Express to the culture medium of cells in which your gene is under the control of any TRE-containing promoter. Tet-Express makes tetracycline-controlled transcription a rapid process for all cell types, and is particularly advantageous for cell types that are not amenable to sequential rounds of clonal selection.
What is Tet-Express?
Tet-Express is a version of Clontech’s Tet-Off Advanced transactivator protein that has been modified and optimized for self-transduction, i.e., it has the ability to transport itself across cell membranes into the nucleus via protein transduction pathways. Since Tet-Express binds and activates expression in the absence of tetracyclines, doxycycline is not required for gene activation. An Intensifier Reagent included with each vial of Tet-Express increases protein transduction efficiency.
Low Basal Expression, High Maximal Expression & Rapid Induction
A TRE3G vector is included with every Tet-On 3G and Tet-Express system and contains an inducible promoter, PTRE3G or PTRE3GV. The latter is a version optimized for use in retroviral and lentiviral vectors. These promoters are the most advanced TRE-containing promoters available, and ensure very low basal expression and high maximal expression after induction. (For more information, see the Tet-On 3G page.) Because PTRE3G lacks binding sites for endogenous mammalian transcription factors, and since the minimal CMV promoter is inactive in the absence of a tetracycline transactivator protein, basal expression from PTRE3G is the lowest of any TRE-containing promoter available so far. Basal expression is undetectable by Western analysis, but expression can be induced to very high levels in the presence of a tetracycline transactivator. The Tet-Express System provides rapid induction of high levels of gene expression in a wide variety of cell types, as described in our Tet-Express technical note.
Choice of Multiple Different Tet-Express System Formats
The Tet-Express Inducible Expression System is available in seven plasmid varieties, as well as lentiviral and retroviral formats. Plasmid formats include:
The Tet-Express Inducible Expression System (Bicistronic Version), which allows inducible coexpression of two genes of interest
The Tet-Express Inducible Expression System (with mCherry) and the Tet-Express Inducible Expression System (with ZsGreen1), which allow monitoring of inducibility via induced coexpression of a red (mCherry) or green (ZsGreen1) fluorescent protein.
The Tet-Express Inducible Expression System (Bidirectional Version), which allows equivalent co-regulated and simultaneous expression two genes of interest
The Tet-Express Inducible Expression System (Bidirectional, mCherry) and the Tet-Express Inducible Expression System (Bidirectional, ZsGreen1), which allow indirect monitoring of the expression of a target gene via co-induced expression of a bright red (mCherry) or green (ZsGreen1) fluorescent protein
Each format is sold as a complete system. The retroviral (Retro-X) and lentiviral (Lenti-X) formats are supplied with complete viral packaging systems.