A transgenic rat with ubiquitous expression of firefly luciferase gene

In vivo imaging strategies provide cellular and molecular events in real time that helps us to understand biological processes in living animals. The development of molecular tags such as green fluorescent proteins and luciferase from the firefly Photinus pyralis has lead to a revolution in the visualization of complex biochemical processes. We developed a novel inbred transgenic rat strain containing firefly luciferase based on the transgenic (Tg) technique in rats. This Tg rat expressed the luciferase gene ubiquitously under control of the ROSA26 promoter. Cellular immune responsiveness against the luciferase protein was evaluated using conventional skin grafting and resulted in the long-term acceptance of Tg rat skin on wild-type rats. Strikingly, organ transplant with heart and small bowel demonstrated organ viability and graft survival, suggesting that cells from luciferase-Tg are transplantable to track their fate. Taking advantage of the less immunogenic luciferase, we also tested the role of hepatocyte-infusion in a liver injury model, and bone marrow-derived cells in a skin defect model. Employed in conjunction with modem advances in optical imaging, this luciferase-Tg rat system provides an innovative animal tool and a new means of facilitating biomedical research such as in the case of regeneration medicine.