Figure 3. Luciferase expression in BALB/c mice receiving deep or superficial injections of Luc gene. The depth of luciferase expression was verified by 3D BLI 2 h after Luc gene administration. The “center of mass” of luciferase expression localized between 2.0–3.0 mm in mice receiving deep (A) and between 1.0–1.5 mm in mice receiving superficial Luc gene injections (D). Skin was excised post mortem and monitoring was repeated directly after. In mice receiving deep injections (A) luciferase activity was localized to the muscle tissues (B) while none was registered in the skin (C). On contrary, in superficially injected animals (D) luciferase activity was recorded in the skin (F) but not in the muscles (E).