To: PuddleGlum who wrote (1274 ) 11/22/2002 10:34:28 AM From: tuck Read Replies (1) | Respond to of 1784 Long time followers of this thread may recall my ethical fondness for Xenogen, a company that missed the IPO window a couple of years back. It markets in vivo imaging systems based on firefly luciferase that mean less slaughter of experimental animals (chiefly mice) and continuous monitoring of their condition during preclinical studies. It's still out there, and recently did a deal with MLNM. Meanwhile these other folks seem to have refined the technique a bit. In vivo monitoring of protein-protein interactions would be neat! >>Published online before print November 18, 2002 Proc. Natl. Acad. Sci. USA, 10.1073/pnas.242594299 Medical Sciences Noninvasive imaging of protein-protein interactions in living subjects by using reporter protein complementation and reconstitution strategies R. Paulmurugan *, Y. Umezawa , and S. S. Gambhir *¶|| *Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, University of California Los Angeles-Jonsson Comprehensive Cancer Center, and ¶Department of Biomathematics, University of California School of Medicine, Los Angeles, CA 90095-1770; and Department of Chemistry, School of Science, University of Tokyo, Hongo, Tokyo 113-033, Japan Communicated by Michael E. Phelps, University of California, Los Angeles, CA, October 2, 2002 (received for review August 25, 2002) In this study we have developed bioluminescence-imaging strategies to noninvasively and quantitatively image protein—protein interactions in living mice by using a cooled charge-coupled device camera and split reporter technology. We validate both complementation and intein-mediated reconstitution of split firefly luciferase proteins driven by the interaction of two strongly interacting proteins, MyoD and Id. We use transient transfection of cells and image MyoD-Id interaction after induction of gene expression in cell culture and in cells implanted into living mice. Techniques to study protein-protein interactions in living subjects will allow the study of cellular networks, including signal transduction pathways, as well as development and optimization of pharmaceuticals for modulating protein-protein interactions. -------------------------------------------------------------------------------- ||To whom correspondence should be addressed at: Crump Institute for Molecular Imaging, University of California School of Medicine, B3-399A BRI, 700 Westwood Plaza, Los Angeles, CA 90095-1770. E-mail: sgambhir@mednet.ucla.edu. www.pnas.org/cgi/doi/10.1073/pnas.242594299<< Cheers, Tuck