The construct encoding full-length human amyloid beta precursor protein (APP695) with V717I (London) mutation was obtained from Dr. Oksana Berezovska (Massachusetts General Hospital, Boston, MA, USA; GeneBank accession no: NM_201414). The human presenilin 1 (PS1) construct with ΔE9 mutation was a kind gift from Dr. John Hardy (NIH, Bethesda, MD, USA; GeneBank accession no: NM_000021). To introduce K670N/M671L (Swedish) mutations into APP695 (London) gene, we performed a site-directed mutagenesis using a mutagenic primer set, 5′-cggaggagatctctgaagtgaatttggatgcagaattccga-3′ and 5′-tcggaattctgcatccaaattcacttcagagatctcctcc g-3′ by using QuikChange Site-Directed Mutagenesis Kit (Agilent Technologies, Santa Clara, CA, USA). APP (Swedish/London) and/or PS1ΔE9 cDNAs were then PCR-amplified with Pfu (New England Biolabs, Ipswich, MA, USA) and cloned into lentiviral polycistronic CSCW-IRES-GFP or CSCW-IRES-mCherry vectors to generate CSCW-APP-GFP, CSCW-PS1ΔE9-mCherry and CSCW-APP-IRES-PS1ΔE9-IRES-mCherry. The parental CSCW-IGs vector was provided by Massachusetts General Hospital (MGH) viral core (http://www2.massgeneral.org/ncs/neuro_core_VectorDevelopmentandProduction.htm). The primers used for the cloning were: APP, 5′-caccgctagccagggtcgcgaatgctgc-3′ and 5′-ggcgtcgacctagttctgcatctgctc-3′; PS1, 5′-caccgctagcagttgctccaatgacagagttac-3′ and 5′-gacctcgagctagatataaaattgatggaatgc-3′. The amplified APP or PS1 genes were double-digested with NheI/SalI or NheI/XhoI and ligated to either CSCW-IRES-GFP or CSCW-IRES-mCherry vectors. To make CSCW-APP-IRES-PS1ΔE9-IRES-mCherry vector, the APP-IRES segment of CSCW-APP-IRES-GFP vector
