Figure 1A: Male and female mice were imaged in the ventral (left) and dorsal (right) regions. High basal luciferase expression was observed in males and females in feet, tail, ear, and mouth, all areas where bare skin is visible. Luciferase expression was observed in male gonads in some animals.

Figure 1B. β-actin-luc tissue expression survey from 2 male and 2 female mice (Fig. 1A). Data are expressed in Relative Light Units (RLU)/mg protein.

Tissue Expression of Luciferase signal

Luciferase expression of the β-actin-luc transgene was examined in extracts of tissue dissected from adult male and female mice from the β-actin-luc LPTA® animal model. Luciferase expression was highest in skeletal muscle, thymus skin, heart, bone, pancreas, and was detectable in all tissues examined including white blood cells (Fig. 1B). The bar graph is plotted with a logarithmic ordinate scale to graphically display all data. The expression data agree with ex vivo study data (not shown) and published work examining constitutive promoter-driven transgene expression.1,2 Luciferase expression was also examined in white blood cells from β-actin-luc mice (Fig. 1C (below)). Whole blood was harvested and spun to enrich for white blood cells. Cells were then serially diluted in a 96-well plate and placed in media containing luciferin substrate.

Imaging Recommendations

Anesthetize mice prior to injection of luciferin and measurement of luciferase transgene expression. Optimal imaging occurs between 10 and 20 minutes following intraperitoneal injection of luciferin.