FIG. 1.

Comparing luciferase and Cre vectors in mice. (A) Diagram of luciferase activation in L-S-L Luc mice by Cre-expressing vector. Two luciferase cassettes are shown to depict the presence of two target genes per cell in homozygous mice. (B) Comparison of luciferase imaging in female L-S-L Luc mice injected by the intravenous or intramuscular route with ssAAV8-Luc or scAAV8-Cre. Pseudocolor of the day 6 image scale bar is shown. (C and D) Luciferase expression after intravenous injection of scAAV8-Cre into female L-S-L Luc mice. The total photon flux over 10 min per mouse is denoted for both doses by solid lines; relative copy number of the Cre–transgene (dashed lines) was measured by qPCR of total DNA isolated from livers of mice harvested on days 1, 4, 21, and 320 postadministration. The copy number of the reference gene RNase P was used to correct for variation in the amounts of DNA. The final results are expressed as n-fold differences in the Cre–transgene gene copy number relative to the RNase P gene (n=4).