The tetracycline-responsive promoter contains functional interferon-inducible response elements.

Area of Science:

• Molecular Biology
• Virology
• Immunology

Background:

• Tetracycline (tet)-responsive expression vectors enable controlled protein induction in mammalian cells for research.
• This system is crucial for in vitro and in vivo experimental studies.

Purpose of the Study:

• To investigate the antiviral effect of interferon-alpha (IFNalpha) on hepatitis B virus using the tet-responsive system.
• To identify and characterize an unexpected feature of the tet-responsive promoter (tet promoter) influenced by IFNalpha.

Main Methods:

• Transient transfection of mammalian cells.
• Sequence inspection of the tet promoter.
• Gel shift assays to detect protein-DNA interactions.

Main Results:

• Interferon-alpha (IFNalpha) was found to stimulate tet promoter activity in a dose- and cell type-dependent manner.
• An IFNalpha-stimulated response element (ISRE)-like sequence was identified within the tet promoter's linker regions.
• Gel shift assays confirmed the binding of IFN-stimulated gene factors to these ISRE-like sequences, mediating promoter stimulation.

Conclusions:

• The tet-responsive expression system exhibits an uncharacterized sensitivity to IFNalpha, impacting its application in cytokine function analysis.
• Mutagenesis of the identified ISREs can render the tet promoter non-responsive to IFNalpha, which is critical for gene therapy applications.