Uses of GFP in transgenic vertebrates.

The ability to express exogenous DNA in vertebrate animals has been invaluable to a wide range of biological studies. Our understanding of processes as diverse as gene expression, cell lineage relationships, and gene function have all benefited from the use of " transgenic " animals. Traditionally, analysis of reporter genes such as lacZ in transgenic animals usually involved killing the animal, precluding many types of experiments. The discovery that green fluorescent protein (GFP) could be used as a reporter for gene expression in living animals (Chalfie et al., 1994) has revolutionized the use of transgenic animals for studying many aspects of biology from development to neuroscience. GFP has several advantages over traditional transgenic markers. Most importantly, GFP can be imaged non-invasively in live animals. GFP also provides superior spatial and temporal resolution. Finally the use of GFP fusion proteins and variants of GFP enable a tremendous variety of experiments to probe biological function. A great deal of progress has been made in recent years in the use of GFP, in techniques for generating transgenic animals, and in techniques for imaging animals. These advances have combined to lead to a dramatic increase in the power of using GFP in transgenic