Figure 2.

Amyloid plaques develop and mature with age in J20 APP tg mice without significant changes in full-length (FL) APP or in its proteolytic processing by β- or α-secretases. a, Hippocampal sections from fixed J20 APP tg brain were paraffin-embedded, then stained for Aβ using R1282 polyclonal antibody. Three-month-old tg sections were virtually plaque-free, whereas some plaques had formed by age 12 months. By 24 months, abundant diffuse and dense-core plaques populated the hippocampus. b, Representative blot of brain lysates of 3- and 24-month-old tg mice and wt littermate loaded onto denaturing SDS-PAGE, then blotted for full-length APP and its C-terminal fragments (CTFs) (WB was performed with polyclonal C7) or to α-tubulin (WB was performed with polyclonal tubulin-α). c, Summary ratios of immunoreactive signals at 24- versus 3-month-old tg mice, for full-length APP and C-terminal fragments normalized to the α-tubulin signal. n = 3 mice per group; signal quantification by Licor Odyssey.