Green Fluorescent Protein

(Abbreviation: GFP). A protein derived from a species of jelly fish, that fluoresces when exposed to ultra violet light. Its encoding gene has been isolated and is replacing GUS as a reporter gene in plant transgenesis, since it can be assayed non-destructively in real time.

A protein naturally occurring in some animals including jelly fish that spontaneously fluoresces. It can be used as a noninvasive marker in living cells by attaching it to different proteins and then letting it fluoresce so as to track the cell.