Fig. 3

Generation of forebrain neuron-specific FT knockout mice. A Schematic representation of the 3-step breeding strategy to generate APP/PS1 mice harboring homozygous FT knockout in forebrain neurons (APP/PS1/FTnKO) and littermate controls. B Representative immunoblot images of FT-β and HDJ-2, a well-known farnesylated protein that is widely used as a marker for farnesylation, in cortical, hippocampal, cerebellar tissue homogenates of WT and FTnKO mice at 3 and 6 months of age. Unfarnesylated HDJ-2 band is detected in the forebrain region (cortex and hippocampus), but not in the cerebellum, of FTnKO mice at 3 months, and the level is elevated at 6 months, confirming both brain region- and age-dependent deletion of FT. C, D Immunoblot analysis of representative small GTPases in membrane (M) and cytosolic (C) fractions of cortical tissue lysates of FTnKO mice compared with WT controls (n = 5/genotype). Membrane-associated FT substrates, farnesylated H-Ras and Rheb, are reduced significantly or trending reduction in FTnKO compared with WT controls, whereas membrane levels of GGT substrate RhoA are not affected, confirming the specificity of FT deletion. E Representative immunoblot images of HDJ-2 in cortical tissue homogenates of APP/PS1 and APP/PS1/FTnKO mice at 9–10 months of age. F, G Immunoblot analysis of representative small GTPases in membrane (M) and cytosolic (C) fractions of cortical tissue lysates from APP/PS1 and APP/PS1/FTnKO mice at 9–10 months of age (n = 5/genotype). Wilcoxon signed rank-order test, 2-tailed; ^#p = 0.078; *p < 0.05; **p < 0.01