pTiGer Reporter Plasmids

pTiGer-reporter: plasmids for Tet-inducible Gene expression or repression (controls)

InvivoGen's pTiGer-reporter plasmid family features a Tetracycline (Tet)-inducible expression cassette containing the strong composite CMV-EF1 promoter modified to integrate a tetracycline response element (TRE), a reporter gene, and an efficient terminator of transcription. Each plasmid carries an antibiotic resistance marker for selection in both mammalian cells and bacteria.

Our pTiGer-reporter plasmids are functionally validated by transfection of the tetracycline repressor-expressing RepTor™ cells (see below).

— pTiGer2/3/4-SEAP expresses secreted embryonic alkaline phosphatase

— pTiGer2/3/4-Lucia expresses Lucia luciferase

— pTiGer2/3/4-eGFP expresses enhanced green fluorescent protein

These three plasmids are selectable either with Zeocin^® (pTiGer2), Hygromycin (pTiGer3), or Puromycin (pTiGer4), in both E. coli and mammalian cells.

Control of the TiGer tet-on system

pTiGer-reporter plasmids are a collection of control vectors for the pTiGer-mcs plasmids.
They can be transiently transfected into RepTor™ cells to demonstrate that the TiGer tet-on system works properly, i.e. no background reporter expression without doxycycline and strong reporter expression with doxycycline.
Moreover, the transfected RepTor™-reporter cells allow you to detect the presence of contaminating tetracyclines and derivatives in lots of fetal bovine serum used for cell culture. Indeed, although the TiGer tet-on system ensures maximal repression of the gene of interest (GOI), residual amounts of tetracyclines found in some serum lots can lead to unintended GOI basal expression. 

Induction of the reporter expression in just two steps

Step 1: The pTiGer-reporter plasmid is transiently or stably transfected into HEK-RepTor™ or A549-RepTor™ cells. These cells express the tetracycline repressor (TetR) which binds to the TRE within the plasmid, repressing GOI expression [1].

Step 2: The addition of doxycycline, a synthetic derivative of the tetracycline antibiotic, leads to TetR release and reporter gene transcription. The SEAP and Lucia activities are readily assessable in the cell culture supernatant using QUANTI-Blue™ and QUANTI-Luc™ 4 detection reagents.

Of note, the composite Tet-inducible CMV-EF1-TRE promoter in the pTiGer plasmids confers strong expression and full induction of the reporter gene in the presence of 1 ng/ml of doxycycline. This low antibiotic dose ensures minimal toxicity or metabolic changes [2].

Choose among pTiGer-mcs vectors for cloning your GOI

Plasmids of the pTiGer-mcs family feature a tet-inducible expression cassette containing the strong composite CMV-EF1 promoter modified to integrate a TRE, a convenient multiple cloning site (mcs), and an efficient terminator of transcription. Each plasmid carries an antibiotic resistance marker (i.e. Zeocin^®, Hygromycin, or Puromycin).

References:

1. Hillen, W., Wissmann, A. (1989). Tet repressor-tet operator interaction. Protein-Nucleic Acid Interaction. DOI: 10.1007/978-1-349-09871-2_7.
2. Moullan, N., et al., (2015). Tetracyclines disturb mitochondrial function across eukaryotic models: a call for caution in biomedical research. Cell Rep. 10(10):1681-91.