What is a tetR promoter?

Tetracycline-controlled gene expression is based upon the mechanism of resistance to tetracycline antibiotic treatment found in gram-negative bacteria. In nature, the Ptet promoter expresses TetR, the repressor, and TetA, the protein that pumps tetracycline antibiotic out of the cell.

What does tetR bind to?

In the absence of Tc, TetR binds to the bacterial DNA as a homodimer and represses the resistance genes.

How does Tet on work?

Tetracycline (Tet) technology allows precise, reversible, and efficient spatiotemporal control of gene expression. This “on demand” gene induction mimics disease onset and disease progression. When coupled with Cre recombinase, Tet technology allows one to selectively shut down target gene expression.

Is the tTAV protein an activator or a repressor?

Positive feedback is generated via basal expression of the tTAV activator protein, a fusion of the tetracycline-binding domain (tetR) and the herpes simplex virus transcriptional activator (VP16) [13].

How does TetR work?

TetR represses the expression of TetA, a membrane protein that pumps out substances toxic to the bacteria like Tc, by binding the tetA operator. In Tc-resistant bacteria, TetA will pump out Tc before it can bind to the ribosome because the repressive action of TetR on TetA is halted by binding of Tc to TetR.

What is the function of TetR in the regulation of tetracycline resistance?

In bacteria, the tetracycline repressor (tetR) binds regulatory sequences (tetO) located upstream of the tetracycline resistance gene to suppress gene expression. Promoter activity resumes when tetracycline binds tetR, rendering it incapable of binding to tetO (Gossen et al., 1993).

What is Tet-on plasmid?

The Tet system is a conditional gene expression system where transcription is turned on or off in the presence of tetracycline or doxycycline. It affords very tight control over expression compared to other inducible systems and is reversible.

What is tTAV?

Tetracycline-controlled transactivator (tTAV) is a synthetic protein coding sequence based on a fusion of sequences from Escherichia coli and Herpes simplex virus (VP16 transcriptional activator). tTAV is under the control of its own binding site, tetO.

What is the TetR gene?

TetR is the repressor of the tetracycline resistance element; its N-terminal region forms a helix-turn-helix structure and binds DNA. Binding of tetracycline to TetR reduces the repressor affinity for the tetracycline resistance gene (tetA) promoter operator sites.