Noninvasive Quantitative Imaging of Protein-Protein Interactions in Living Subjects

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 99; no. 5; pp. 3105 - 3110
• Main Authors: Ray, P., Pimenta, H., Paulmurugan, R., Berger, F., Phelps, M. E., Iyer, M., Gambhir, S. S.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 05.03.2002; National Acad Sciences; The National Academy of Sciences
• Subjects: Animals; Biological Sciences; Cell Culture Techniques; Cell Line, Transformed; Cell lines; Cellular biology; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drug interactions; Fungal Proteins - genetics; Fungal Proteins - metabolism; GAL4 protein; Gene Expression; Genes, Reporter; Herpes Simplex Virus Protein Vmw65 - genetics; Herpes Simplex Virus Protein Vmw65 - metabolism; Humans; Imaging; Inhibitor of Differentiation Protein 1; Luciferases - genetics; Medical imaging; Mice; MyoD protein; MyoD Protein - genetics; MyoD Protein - metabolism; NF-kappa B - genetics; Plasmids; Promoter Regions, Genetic; protein-protein interactions; Proteins; Proteins - metabolism; Rats; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Reporter genes; Repressor Proteins; Rodents; Saccharomyces cerevisiae Proteins; Transactivation; Transcription Factors - genetics; Transcription Factors - metabolism; Transfection; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha - pharmacology; Yeasts
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.052710999

We are developing methods to image molecular and cellular events in living subjects. In this study, we validate imaging of protein-protein interactions in living mice by using bioluminescent optical imaging. We use the well studied yeast two-hybrid system adapted for mammalian cells and modify it to be inducible. We employ the NF-κB promoter to drive expression of two fusion proteins (VP16-MyoD and GAL4-ID). We modulate the NF-κB promoter through tumor necrosis factor α. Firefly luciferase reporter gene expression is driven by the interaction of MyoD and ID through a transcriptional activation strategy. We demonstrate the ability to detect this induced protein-protein interaction in cell culture and image this induced interaction in living mice by using transiently transfected cells. The current approach will be a valuable and potentially generalizable tool to noninvasively and quantitatively image protein-protein interactions in living subjects. The approaches validated should have important implications for the study of protein-protein interactions in cells maintained in their natural in vivo environment as well as for the in vivo evaluation of new pharmaceuticals targeted to modulate protein-protein interactions.