Generation and characterization of tg mice expressing α-syn, APP or α-syn/APP under the mThy1 promoter. A. Schematic representation of the α-syn and APP single tg mice. B. Levels of hAPP mRNA and hα-syn mRNA expressed as a ratio to the housekeeping gene GAPDH in non-tg APP, α-syn, and α-syn/APP tg mice. Mice express comparable levels of hAPP mRNA in the APP and α-syn/APP tg mice, as well as similar levels of α-syn mRNA in the α-syn and α-syn/APP tg mice. C. Laser scanning confocal microscopy studies confirmed that in the α-syn/APP tg mice the same neuronal populations co-express human amyloid precursor protein (hAPP) and human α-syn (hα-syn); scale bar = 10 μm. D Representative Western blot and E analysis showed the presence of native α-syn (14 kDa) in the membrane fraction all mice with the most enhanced accumulation of α-syn (monomeric and oligomers) occurring in α-syn/APP mice when compared to the α-syn tg mice (p-value < 0.05). F. Representative Western blot and G analysis of hAPP revealed that full length APP and Aβ levels were comparable between APP tg and α-syn/APP tg mice and APP. For analysis, N = 6 mice (3–4 months old) from each line were utilized. * = p-value < 0.05 by one-way ANOVA with a Tukey-Kramer post hoc analysis.