RESUMEN
The green fl uorescent protein (GFP) has become an extremely popular reporter molecule in contemporary cell biology research in a relatively short span of time (fi gure 1). GFP fl uorescence is extensively used as a tool for monitoring gene expression, localisation, mobility, traffi c, and interaction of various membrane and cytoplasmic proteins. The major advantage of GFP as a fl uorophore is its intrinsic, cofactor-independent fl uorescence, which exhibits remarkable stability in the presence of denaturants and over a wide range of pH (Tsien 1998). In addition to visualisation by fl uorescence microscopy, GFP-tagged proteins can be monitored by a variety of techniques such as fl uorescence resonance energy transfer (FRET), fl uorescence recovery after photobleaching (FRAP) and fl uorescence correlation spectroscopy (FCS). The Nobel Prize in chemistry in 2008 was awarded for the discovery and development of GFP to Osamu Shimomura, Martin Chalfi e and Roger Tsien. GFP was discovered by Shimomura in the jellyfi sh Aequorea victoria (fi gure 2) in the early 1960s (Shimomura et al. 1962). It took almost three decades for the gene that encodes GFP to be cloned (Prasher et al. 1992). Subsequently, it was shown by Martin Chalfi e and co-workers that GFP could be expressed in heterologous systems (Chalfi e et al. 1994). This Figure 1. Number of publications (year-wise) in which the words green fl uorescent protein (GFP) appear either in the title or abstract (data taken from PubMed). This list is not exhaustive.