Q. What is green fluorescent protein (GFP)?

Green fluorescent protein is a protein which is found in a luminescent jellyfish (Aquorea victoria) that lives in cold waters of northern Pacific. Bioluminescence is the production of light by living organisms. These jellyfish comprise two proteins: a bioluminescent proteincalled aequorin which emits blue light, and an accessory green fluorescent protein (GFP). Though what we actually see when jellyfish fluoresces is the conversion of blue light emitted by aequorin to a green light-a metabolic reaction facilitated by GFP. As GFP is simply a protein, it is frequently used both as a marker for gene transfer and for localization of proteins. There is a range of green fluorescent proteins which can glow different colors.