Tetracycline-regulated expression system without viral transactivators
T-REx™ The system produces higher levels of inducible expression than any other regulated mammalian expression system. It utilizes the intact CMV promoter and adds control elements from the bacterial tetracycline resistance operon to effectively inhibit and repress transcription from known strong mammalian promoter sequences (1,2).
Specific Activation
T-REx™ utilizes a repressor mechanism to block transcription from the strong CMV promoter in the absence of tetracycline. Because T-REx™ system elements do not use viral transactivators, you can achieve high-level expression from the intact CMV promoter without secondary non-specific activation of host genes.
T-REx™ Mechanism
T-REx™ transcriptional control elements are shown in Figure 1. Two tetracycline operator sequences (TetO2) have been inserted into the CMV promoter between the TATA box and the transcription initiation site. The TetO2 sequence itself has no effect on expression. When tetracycline repressor protein (TR) is present, it effectively binds to the TetO2 site and blocks transcription initiation. Tetracycline added to the culture medium binds to the TR protein and changes its conformation. This change causes the TR protein to release the TetO2 site, thereby inhibiting transcription from the CMV promoter. High-level expression of genes of interest can be achieved (Figure 2). Expression levels can be modulated based on tetracycline concentration and can be induced to levels achieved using constitutive CMV expression vectors.
T-REx™ is a powerful inducible mammalian expression system capable of regulating expression from the intact human cytomegalovirus (CMV) enhancer promoter. The T-REx™ inducible expression vector has the following features:
•The complete CMV enhancer promoter sequence contains two copies of the tetracycline operator TetO2 sequence for achieving high levels of Regulated expression
• Zeocin™ or hygromycin resistance genes for efficient mammalian cell line selection
• Large-molecule multiple cloning sites for simplified cloning
Additionally, pcDNA™4 /TO/myc-His provides the c-myc epitope for use with anti-myc antibodies and polyhistidine (6xHis) sequences Rapid detection of recombinant proteins simplifies purification of recombinant proteins using nickel chelating resin and detection with anti-His (C-terminal) antibodies.
Provides regulatory vector pcDNA™6/TR to achieve high-level expression of tetracycline repressor (TR) protein. This vector expresses the Blasticidin resistance gene to rapidly screen mammalian cell lines that stably express TR protein.
For Research Use Only. Not for use in diagnostic procedures.