Reporter mice are mouse strains that express fluorescent proteins, bioluminescent proteins, or biochemical tags.

Reporter expression enables visualization and semi-quantification of target gene expression as well as cell type or tissue-specific labeling, which also allows for observation of cell migration and differentiation.

Furthermore, reporters tagged to the target gene may be used to identify protein subcellular localization.

While commonly employed fluorescent reporters such as EGFP, tdTomato, ZsGreen and YFP are available for purposes as mentioned above, special reporters such as GCaMPs enable functional readouts such as calcium influxes, effluxes and waves (jYCaMP and jRGECO1a).