Green fluorescent protein

The green fluorescent protein (GFP) is a protein from the jellyfish Aequorea victoria that fluoresces green when exposed to blue light. This process takes place when the protein aequorin, also produced by Aequorea victoria, interacts with Ca2+ ions thus emitting a blue glow.

Related Topics:
Protein - Jellyfish - Aequorea victoria - Fluoresces - Aequorin

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The wild type GFP from Aequorea victoria has a major excitation peak at a wavelength of 395 nm and a minor one at 475 nm. Its emission peak is at 509 nm which is in the lower green portion of the visible spectrum. The GFP from the sea pansy has a single major excitation peak at 498 nm.

Related Topics:
Aequorea victoria - Wavelength - Visible spectrum

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In cell and molecular biology, the GFP gene is frequently used as a reporter of expression. In modified forms it has been used to make biosensors, and many animals have been created that express GFP as a proof of concept that a gene can be expressed throughout a given organism.

Related Topics:
Cell - Molecular biology - Gene - Reporter of expression - Biosensor

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One of the most powerful uses of GFP is to express the protein in small sets of specific cells. This allows researchers to optically detect specific types of cells in vitro (in a dish), or even in vivo (in the living organism). The GFP gene can be introduced into organisms and maintained in their genome through breeding, or local injection with a viral vector can be used to introduce the gene.

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Due to this widespread usage different mutants of GFP have been engineered over the last few years: some mutants have been produced with increased fluorescence and the protein major excitation peak has been shifted to 490 nm with the peak emission kept at 509 nm. Color mutants have been obtained from the GFP gene as well: in particular the cyan fluorescent protein (CFP) and the yellow fluorescent protein (YFP) are two colour variants employed for fluorescence resonance energy transfer (FRET) experiments.

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eGFP is an enhanced green fluorescent protein which is also a commonly used gene reporter.

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Some images of transgenic GFP organisms. From left to right C. elegans, cloned EGFP pig (from Prather lab), beta-barrel structure of GFP (from Zimmer lab), bacterial colonies of GFP and BFP (from Clontech), GFP-mouse (from Tsien lab), GFP-daisy (from Shiva lab)

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