Seeing is believing: Non-invasive, quantitative and repetitive imaging of reporter gene expression in living animals, using positron emission tomography

The ability to monitor reporter gene expression in living animals and in pa tients will permit longitudinal examinations both of somatically transferre d DNA in experimental animals and patients and of transgenic constructs exp ressed in experimental animals. If investigators can non-invasively monitor the organ and tissue specificity, the magnitude and the duration of gene e xpression from somatically transferred DNA and from transgenes, conceptuall y new experimental paradigms will be possible. If clinicians can non-invasi vely monitor the location, extent and duration of somatically transferred g enes, they will be better able to determine the correlations between expres sion of therapeutic genes and clinical outcomes. We have developed two repo rter gene systems for in vivo reporter gene imaging in which the protein pr oducts of the reporter genes sequester positron-emitting reporter probes. T he "PET reporter gene" dependent sequestration of the "PET reporter probes" is subsequently measured in living animals by Positron Emission Tomography (PET). We describe here the principles of PET reporter gene/PET reporter p robe in vivo imaging, the development of two imaging systems, and the valid ation of their ability to non-invasively, quantitatively and repetitively i mage reporter gene expression in murine viral gene transfer and transgenic models. J. Neurosci. Res. 59: 699-705, 2000. (C) 2000 Wiley-Liss, Inc.