A naturally fluorescent protein obtained from the jellyfish Aequorea victoria and used as a marker for identifying cells containing recombinant DNA or for localizing specific proteins in cells. It absorbs blue light and emits a green fluorescence, and hence the abundance and location of GFP in cells can be visualized microscopically under ultraviolet light. The GFP gene is used as a reporter gene to pinpoint cells expressing recombinant DNA, by causing GFP to be synthesized and the cell to glow green. Moreover, GFP can tag a protein of interest so that its abundance and distribution within the cell can be assessed. This is achieved by introducing recombinant DNA in which the GFP gene is fused to the target protein gene under the control of its normal promoter. When this fusion gene is expressed, the resultant fusion protein can readily be visualized within the cell and its fate tracked over time. Several colour variants of GFP are now available.
Subjects: Biological Sciences.