GFP Transfection

Flow cytometry can accurately quantitate reporter gene expression (For example, Green Fluorescent Protein, GFP) in each cell in a population being transfected. Co-transfection of a reporter plasmid and a reference plasmid can be quite variable in normal human cells, making interpretation difficult in reporter gene assays. However using flow cytometry, reporter and reference plasmid expression can both be quantitated at the single cell level, even in cases of low transfection efficiency. In addition, heterogeneity in reporter expression and transient effects in gene expression can be examined.

Since a flow cytometer can simultaneously collect multi-parametric data, propidium iodide can be used to monitor the DNA content of cells of varying viabilities, identifying apoptotic cells with sub G1 DNA content. A direct approach of using fluorochrome-conjugated antibodies to the transfected gene product can also be used to screen cell populations. As opposed to bulk detection approaches examining the whole well in a microplate, flow cytometry analysis of individual viable cells can pick up very rare events and can find rare subpopulations.

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