Fig. 1. The MloxP construct and PrP expression in tg37 and tg46 mice. (A) MloxP construct containing the floxed murine PrP coding region (PrP ORF, white box) within the CosSHaTet expression vector (exons represented by grey boxes) before (upper image) and after Cre-mediated recombination (lower image). Black triangles represent loxP sequences. The annealing site of DNA probe A used in Southern blotting is shown. (B) Western blotting showing PrP expression in wild-type, tg37 and tg46 mouse brains using antibody 6H4 (Prionics). β-actin was simultaneously detected to control for loading differences between the samples. After quantitation of relative signal intensities, expression levels of PrP by tg46 and wild-type mice are similar and ∼3-fold lower than in tg37 mice.