Dr. Sam Gambhir's group has developed a self-complementing firefly luciferase fragment system for assaying and imaging cellular events in cells and in living animals. From this study, they identified luciferase fragments capable of self-complementation to produce luciferase activity in different cell lines and in living mice. The signal produced by the complementing fragments is sufficient for effective assaying in cells and imaging in living animals. This work is significant because it is the first demonstration of self-complementation of any optical reporter protein.
This technology can be utilized for many different applications such as screening macromolecular delivery vehicles (such as developing new transfection agents, protein delivery agents, cell permeable peptides development, and so on), studying cell-cell fusions, determining the intracellular localization of proteins, and developing intracellular phosphorylation sensors based on the fragment complementation. This system represents an important step for studying cellular localization because all existing assays only provide semi-quantitative analysis. Studying cell-cell fusion and the associated transformation of the cells is important for the quantitative cellular analysis of stem cells in response to co-culturing with other type of cells. Similarly, rapid screening of peptides and lipids for their macromolecular delivery efficiency is possible using this system.