Imaging Studies Using Reporter-Gene Transgenic Rats A. Kimura, E. Kobayashi, in Encyclopedia of Neuroscience, 2009

Luciferase Luciferases comprise a group of enzymes that emit light in the presence of oxygen and a substrate (luciferin). Such a luciferin–luciferase system is found in nature, for example, in bacteria (Vibrio harveyi), dinoflagellates (Gonycaulax), and the firefly (Photinus pyralis). These luciferases, in particular the eukaryotic firefly luciferase (Luc), have been commonly used as a light probe in a number of biological experiments, including promoter activity assays. Furthermore, thanks to recent advances in high-sensitivity photon-counting video cameras, a number of studies have employed Luc as a reporter gene in real-time noninvasive in vivo imaging. This in vivo imaging allows the visualization of the spatial and temporal behavior of Luc-expressing cells in living animals; for example, growth of tumor cells, trafficking of immune cells, and migration of transplanted cells. These imaging studies using Luc-labeled cells have offered new insights that could not have been gained using conventional histological approaches.