Single cell reporter assay using cell surface displayed Vargula luciferase.

Area of Science:

• Biotechnology
• Molecular Biology
• Reporter Gene Assays

Background:

• Traditional reporter genes like firefly luciferase require cell lysis for enzyme activity measurement, hindering continuous monitoring.
• Internal expression of reporter enzymes complicates real-time gene expression analysis and single-cell studies.
• Existing methods face challenges in non-invasive, continuous gene expression tracking.

Purpose of the Study:

• To develop a novel reporter gene system for continuous, non-invasive gene expression monitoring.
• To engineer a cell surface-displayed Vargula hilgendorfii luciferase for real-time analysis.
• To demonstrate the utility of this reporter system in single-cell gene expression studies.

Main Methods:

• Fusion of Vargula hilgendorfii luciferase with a human EGFR transmembrane sequence for cell surface display.
• Expression analysis of the engineered luciferase on the cell surface.
• Co-transfection studies with alkaline phosphatase to validate reporter behavior.
• Utilizing a photon-counting CCD camera for single-cell luminescence detection.

Main Results:

• Successfully engineered and expressed Vargula hilgendorfii luciferase on the cell surface without loss of bioluminescent activity.
• Demonstrated comparable behavior between cell surface-displayed Vargula luciferase and secreted alkaline phosphatase.
• Achieved real-time luminescence monitoring of single cells expressing the surface-displayed reporter gene.
• Validated the reporter system's capability for non-lytic, single-cell gene expression analysis.

Conclusions:

• Cell surface display of Vargula hilgendorfii luciferase provides a robust platform for non-invasive reporter gene assays.
• This novel reporter system overcomes the limitations of cell lysis required by intracellular reporters.
• Enables continuous, real-time monitoring of gene expression at the single-cell level, opening new avenues in biological research.