Noninvasive imaging of reporter gene expression and distribution in vivo

Repeated noninvasive imaging of reporter gene expression is increasingly used for monitoring the expression and location of genes and cells in experimental animals and humans. Development of transgenic animals that express reporter genes in specific tissues/organs or the whole body possess the potential for understanding the course of disease or serve as a syngenic cell/tissue/organ donor to study transplant survival in recipients. In this review, we discuss the major reporter genes used in gene therapy, cell therapy and transgenic animals, including exogenous reporters (herpes simplex virus type 1 thymidine kinase, fluorescent proteins and luciferase) and endogenous reporters (dopamine 2 receptor, transferrin receptor, sodium iodide symporter, β-glucuronidase, and antibody reporter). The clinical potential of these reporter genes is also discussed with regard to their imaging specificity and immunogenicity in humans.