Knockout of the BACE1 gene, but not CatB, in AβPPSwe/Lon mice alters Aβ-related biomarkers. Brain Aβ40 and Aβ42 brain levels (A and B, respectively) were determined by ELISA in AβPPSwe/Lon (control), AβPPSwe/Lon × CatB KO (CatB KO), and AβPPSwe/Lon × BACE1 KO (BACE1 KO) mice. Relative brain levels of CTFβ were assessed by western blots (C) with actin in control westerns; quantitation of CTFβ western blots for the three groups of mice is shown (D). Relative brain levels of sAβPPα were assessed by western blots (E) with actin in control westerns; quantitation of sAβPPα western blots is shown (F). Values are shown as the x ± s.e.m., and n = 10. ***Statistically significant (p < 0.05).