Imaging tri-fusion multimodality reporter gene expression in living subjects. Cancer Res

Imaging reporter gene expression in living subjects with various imag-ing modalities is a rapidly accelerating area of research. Applications of these technologies to cancer research, gene therapy, and transgenic mod-els are rapidly expanding. We report construction and testing of several triple fusion reporter genes compatible with bioluminescence, fluores-cence and positron emission tomography (PET) imaging. A triple fusion reporter vector harboring a bioluminescence synthetic Renilla luciferase (hrl) reporter gene, a reporter gene encoding the monomeric red fluores-cence protein (mrfp1), and a mutant herpes simplex virus type 1 sr39 thymidine kinase [HSV1-truncated sr39tk (ttk); a PET reporter gene] was found to preserve the most activity for each protein component and was therefore investigated in detail. After validating the activities of all three proteins encoded by the fusion gene in cell culture, we imaged living mice bearing 293T cells transiently expressing the hrl-mrfp-ttk vector by mi