γ-secretase activity and Aβ levels are not affected by the presence of htau.

<p>A-C. Brain lysates from WT, APP, PS1, APP/PS1, and APP/PS1/htau animals at 3 to 4 months of age were analyzed using γ-secretase activity assay. PS1 M146V mutation does not alter Aβ40 but significantly increases Aβ42 production, leading to increased Aβ42:Aβ40 ratio in PS1, APP/PS1, and APP/PS1/htau samples. However, no significant difference in γ-secretase activity was found between PS1, APP/PS1, APP/PS1/htau samples. *** p<0.001, one-way ANOVA with Newman-Keuls multiple comparison test. D-F. Aβ ELISA was performed using brain lysates from APP/PS1 and APP/PS1/htau animals. Presence of htau does not change Aβ40 or Aβ42 production. Student t-test, no significant difference.