Tg(APPSw)40Btla

The transgenic insertion comprises four to eight copies of a 650-kb YAC containing the entire 400-kb human amyloid precursor protein gene with the Swiss familial Alzheimer disease (FAD) mutation and approximately 250 kb of flanking human DNA. The double mutation (K670N/M671N) comprises a G-to-A transition converting the lysine codon at position 670 to an asparagine codon and an A-to-C transversion replacing the methionine at amino acid 671 with leucine. RT-PCR and western blot analysis revealed that hemizygous transgenic mice express all major human APP mRNA and protein isoforms in brain, in parallel with the corresponding mouse versions, at approximately three times the levels of the latter. Total brain levels of the Alzheimer disease- associated 42-amino acid amyloid-beta peptide detected by ELISA are 7-8-fold and 15-20-fold higher, respectively, in mice hemizygous and homozygous for the mutant gene than in hemizygotes for the wildtype human gene. Levels of a cell-associated, beta-secretase-generated 13.5 kDa C-terminal peptide containing the amyloid beta domain and of soluble amyloid beta peptides are significantly elevated in brains of mice with the mutant, versus wildtype, transgene, while alpha-secretase products are diminished. (J:42613, J:58050, J:73622)