Green fluorescent protein: Abbreviated GFP. A protein that glows green under fluorescent light. Found naturally in the jellyfish Aequorea victoria, GFP fluoresces green when exposed to blue light. It has a sequence of three amino acids (serine-tyrosine-glycine) which is responsible for its fluorescence.
GFP has been much used in molecular and cell biology research as:
- A reporter of gene expression -- The expression of a gene can be monitored in cells by linking the control sequences for a gene to the GFP structural gene, which serves as a reporter.
- A protein tag -- The GFP structural gene is fused to another gene, producing a fusion protein that is tagged by GFP. The location of this tagged gene can be seen within living cells.
Thus, the fluorescence produced by GFP can serve to reveal where a particular protein is expressed and to monitor protein-protein interactions.