Figure 1

Generation of APP DSL knock-in mice. A. Gene targeting strategy to generate the APP DSL knock-in allele. Wild type mouse exon 16 and 17 (E16, E17) were replaced by a truncated exon 16 (truncE16), double neo-cassette, followed by exon 16 with humanized Aβ sequence and the Swedish mutation (E16*), and exon 17 with the Dutch and London mutations (E17*). TruncE16 and the neo-cassette were flanked by two loxP sites, which were removed after cre-excision. DT: diphtheria toxin, which was lost upon homologous recombination. B. Schematic diagram of amino acid alterations in APP DSL knock-in line. Aβ42 sequence is marked by thin underline. Residues mutated to humanize Aβ are shown in bold and italic; residues with FAD mutations (Swedish: NL, Dutch: Q, and London: I) are shown in thick-underline. TM: transmembrane region. C. Expression of APP is similar in brain lysates of 3-month-old wild type (WT), SL and DSL knock-in lines, as detected by western blot using antibody against the N-terminal region of APP (22C11) or humanized Aβ region (6E10). γ-tubulin was used as loading control. WT: wild type; SL: APP with humanized Aβ region and Swedish and London mutations; DSL: APP with humanized Aβ region and Swedish, Dutch, and London mutations. D. Quantification of C.