GeneSwitch™ Mammalian Expression Kit, complete kit
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Invitrogen™

GeneSwitch™ Mammalian Expression Kit, complete kit

Switch-On Expression from the Lowest Basal LevelsThe GeneSwitch™ System for inducible mammalian expression is ideal for experiments that require theRead more
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Catalog number K106001
also known as K1060-01
Price (USD)
2,595.00
Each
Add to cart
Price (USD)
2,595.00
Each
Add to cart
Switch-On Expression from the Lowest Basal Levels
The GeneSwitch™ System for inducible mammalian expression is ideal for experiments that require the absolute lowest uninduced expression levels. The expression vector pGene/V5-His provides a minimal promoter, GAL4-E1b, consisting of the binding sites for the yeast Gal4 DNA binding protein followed by the TATA sequence from the Adenovirus E1b promoter. Without additional factors, the GAL4-E1b promoter is transcriptionally silent.

To activate transcription from the GAL4-E1b promoter, the GeneSwitch™ regulatory protein is expressed from a minimal TK promoter on the pSwitch vector. The GeneSwitch™ protein has three functional domains:

• Gal4 DNA Binding Domain (Gal4-DBD) to bind the regulatory protein to the GAL4-E1b promoter
• Truncated human Progesterone Receptor Ligand Binding Domain (hPR-LBD) that undergoes a conformational change when it binds the progesterone antagonist, mifepristone
• Transcription activation domain from the NFØB transcription factor p65 (p65AD) to activate transcription from the silent GAL4-E1b promoter

In the absence of mifepristone, the conformation of the hPR-LBD region prevents the GeneSwitch™ regulatory protein from activating transcription from the GAL4-E1b promoter. When mifepristone is added and binds the hPR-LBD region, the GeneSwitch™ regulatory protein assumes a conformation that permits it to stimulate transcription from the GAL4-E1b promoter (Figures 1 and 2).

Induction of the GeneSwitch™ System leads to activation of the gene of interest on the vector pGene/V5-His. In addition, four Gal4 binding sites upstream of the minimal HSV TK promoter on pSwitch can bind the pSwitch regulatory protein. Therefore, adding mifepristone up-regulates production of the regulatory protein (Figure 1). The increased levels of the GeneSwitch™ regulatory protein result in induction of the gene of interest from pGene/V5-His to levels that can approach those of viral promoters.

The GeneSwitch™ Kit offers exceptionally low uninduced and high induced expression levels in mammalian cells. The system provides the expression vector pGene/V5-His with the minimal, synthetic GAL4-E1b promoter that is transcriptionally silent until activated. The GeneSwitch™ regulatory protein binds the GAL4-E1b promoter to activate transcription upon the addition of mifepristone. In addition, the GeneSwitch™ protein upregulates its own expression, leading to amplified expression of the gene of interest from pGene/V5-His. pGene/V5-His offers several features that facilitate expression analysis and purification of recombinant proteins in mammalian cells:

• C-terminal V5 epitope tag for detection with Anti-V5 Antibodies
• C-terminal polyhistidine (6xHis) tag for rapid purification with nickel-chelating resin and detection with Anti-His(C-term) Antibodies
• The Zeocin™ resistance gene for effective selection in both mammalian cells and E. coli
For Research Use Only. Not for use in diagnostic procedures.
Specifications
Constitutive or Inducible SystemInducible
Delivery TypeTransfection
Inducing AgentMifepristone
PromoterE1b (GAL4-E1b)
Product TypeMammalian Expression Kit
Selection Agent (Eukaryotic)Zeocin™
Protein TagHis Tag (6x), V5 Epitope Tag
Cloning MethodRestriction Enzyme/MCS
Quantity1 kit
VectorpGene
Product LineGeneSwitch™
For Use With (Application)Regulated Expression
Unit SizeEach
Contents & Storage
The GeneSwitch™ System Core Kit includes 20 μg of each of the following vectors: pGene/V5-His (A, B, and C), the expression control vector pGene/V5-His/lacZ, and the pSwitch vector. The kit also includes forward and reverse sequencing primers and 100 μg of the inducing agent mifepristone. The GeneSwitch™ Complete Kit includes the Core Kit with 1 g hygromycin and 1 g Zeocin™ at considerable savings. Hygromycin should be stored at +4°C and Zeocin™ at -20°C. Zeocin™ should be protected from exposure to light. All reagents are stable for 6 months when properly stored.

Frequently asked questions (FAQs)

Do you offer any GeneSwitch cell lines?

Sorry, all GeneSwitch cell lines have been discontinued.

What are the characteristic features of the GeneSwitch protein?

The GeneSwitch protein contains functional domains from different transcription factors, allowing it to function as a ligand-dependent transcription factor to activate expression of both the gene of interest and its own gene. The GeneSwitch protein exhibits the following characteristics:

- Since the GAL4 DBD is derived from a yeast protein, the GeneSwitch protein has no effect on endogenous genes and can only activate transcription of genes whose expression is controlled by a GAL4 UAS (i.e., the gene of interest and the regulatory fusion gene).
- The GAL4 DBD binds to an individual 17-nucleotide GAL4-binding site as a homodimer. The pGene/V5-His and pSwitch plasmids contain 6 and 4 copies of the GAL4 binding site, respectively, although it is not known if all of the GAL4-binding sites are occupied at any given time.
- The truncated hPR-LBD contains a 19 amino acid deletion from its C-terminal end that abolishes its ability to bind to progesterone, other endogenous steroid hormones, or other progesterone agonists, but still enables it to bind with high affinity to mifepristone.
- The p65 AD is a strong transcriptional activator but is derived from a human protein, to minimize possible toxic or pleiotropic effects associated with viral transactivation domains.

Why is sequential transfection recommended over co-transfection in the T-REx and GeneSwitch systems?

When a co-transfection is performed, there is no way of testing the double stable cell line for functional TetR or GeneSwitch protein, respectively. On the other hand, when sequential transfection is performed, one can functionally test the generated T-REx or GeneSwitch cell line by transiently transfecting the lacZ expression control plasmid and then picking a clone that shows the lowest basal level of expression of lacZ in the absence of the inducer, and the highest level of lacZ in the presence of the inducer. This clone can then be expanded and used to transfect the T-REx or GeneSwitch expression construct, as the case may be.

What is the main advantage of the GeneSwitch system over the T-REx system? And what is its main disadvantage?

With the GeneSwitch system, it is possible to have the absolute lowest basal levels of expression of the gene of interest, whereas the T-REx system may be a little leaky due to the inevitable presence of tetracycline in FBS. The induced level of expression in the GeneSwitch system can be even higher than that seen with the CMV promoter. The disadvantage of the GeneSwitch system is that the expression does not appear to switch off very easily in culture, although it has been demonstrated to function beautifully in transgenics. The T-REx system, on the other hand, can be switched on and off by the addition and removal of the inducer.

I am interested in a mammalian expression system where I can have regulated expression of my gene of interest. I see that you offer multiple systems for this purpose. Can you describe the main features of each system?

We offer three unique mammalian expression systems for inducible/regulated expression of the gene of interest:

- T-REx system
- Flp-In T-REx system
- GeneSwitch system

Please see below to see how they compare with one another:
System -- Basal Expression Level -- Induced Expression Level -- Response time to Maximal Expression -- Transgenic Appliation
T-Rex system -- Low -- Highest -- High -- Suitable
Flp-In T-REx system -- Lower -- High -- 24-48 hrs -- Suitable
GeneSwitch system -- Lowest -- High -- 24-48 hrs -- Suitable