A reporter gene assay is a kind of cell that has been altered to help scientists understand how genes behave. Sometimes a reporter gene assay is referred to as a reporter cell.
A reporter gene assay is used by a scientist to understand the expression (or activity) of a gene in a cell line of interest.
For example, a scientist might wish to discover the relationships between a specific disease (such as lung cancer) and a particular gene (such as epidermal growth factor receptor or EGFR). Using a reporter gene assay experiment might that help establish a relationship. The research might be conducted in a number of different kinds of living organisms such as cell cultures, plants, or animals (including xenografts).
A reporter gene assay is created by inserting a reporter gene (or reporter) from another organism that has easily measured characteristics into the coding of another gene that the scientist wishes to study. When the gene of interest expresses, changes in the reporter gene are observable and can be measured. It is important that the reporter gene not be natively expressed in the cell or organism under study.
The reporter gene assay is then subjected to experimental conditions and observed. By marking the activity of the reporter gene, a scientist can see how the experimental conditions affect the gene of interest.
Examples of how a reporter gene assay might be useful could include:
Researchers might be interested in investigating genes that are abnormally active (or inactive) in lung cancer tissue.
Pharmaceutical companies might wish to understand the impact that their drugs or drug candidates have on genes known to be involved in ovarian cancer and/or in drug side-effects.
Research institutions might investigate gene activity involved in prostate cancer that can be measured to discover and develop a diagnostic test for the disease.
Biotechnology companies might screen siRNAs to understand which of them are involved in colon cancer and might be altered to cure the disease.
Typically, a reporter gene assay is created by taking the regulatory portion of a gene of interest and attaching the reporter gene to it. A vector containing the new molecule is then inserted into a cell of interest (such as an ovarian cancer cell). The researcher then places the cell in experimental conditions and measures the changes in the reporter gene.
Common examples of reporter genes that might be used in a reporter gene assay are:
Green Fluorescent Protein (GFP--a jellyfish protein that turns green under blue light);
Luciferase enzyme (produces light and found in fireflies);
lacZ gene (encodes the protein
β-galactosidase and causes bacteria to turn blue).