B6.Cg-Tg(APPswe,PSEN1dE9)85Dbo App^tm1Dbo/Mmjax

Stock number: 029770
Product name: APP/PS1 X mAPP ^-/-
Research areas: Mouse/Human Gene Homologs, Neurobiology Research

Description

APP/PS1 X mAPP ^-/- mice carry the human Swedish amyloid precursor protein and the Δe9 presenilin 1 mutation (APP/PS1)85Dbo) transgenes and lack mouse amyloid beta precursor protein (App^tm1Dbo). These mice exhibit reduced microgliosis, reduced cytokine levels and improved memory in the presence of fibrillary Aβ plaques. This strain may be useful for studying the role of APP in microgliosis and plaque formation.

Detailed description

Mice carrying the human Swedish amyloid precursor protein and the Δe9 presenilin 1 mutation (APP/PS1 or Tg(APPswe,PSEN1dE9)85Dbo) and lacking mouse amyloid beta precursor protein (App^tm1Dbo) exhibit reduced microgliosis and reduced cytokine levels (TNFA, IL6) in the presence of fibrillary Aβ plaques. Microglia from the double mutant mice (APP/PS1 X mAPP ^-/-) has reduced migratory ability and proliferation as compared to single mutant APP/PS1 transgenic mice and mAPP ^-/- mice, respectively. In comparison to APP/PS1 transgenic mice, APP/PS1 X mAPP ^-/- mice display improved memory performance, increased exploratory behavior and reduced anxiety. This strain may be useful for studying the role of APP in microgliosis and plaque formation.

Development

To create Stock No. 029770, mice homozygous for the App^tm1Dbo mutation were intercrossed with hemizygous B6.Cg-Tg(APPswe,PSEN1dE9)85Dbo/Mmjax (RRID:MMRRC_034832-JAX [The Jackson Laboratory Stock No. 005864]) mice; subsequent intercrosses generated mice homozygous for the App knockout and hemizygous for the transgene. Mice homozygous for the transgene are not viable. Each allele/transgene is described in more detail below.

To create the App^tm1Dbo null allele, a targeting vector containing neomycin resistance and herpes simplex virus thymidine kinase genes was used to disrupt a region of the App gene encoding the promoter and exon 1. The construct was electroporated into 129S7/SvEvBrd-derived AB2.1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6J blastocysts. The resulting chimeric animals were backcrossed to C57BL/6J for 10 generations.

To create the APP/PS1 are double transgenic mice, two expression plasmids (Mo/HuAPP695swe and PS1-dE9) were designed to each be controlled by independent mouse prion protein (PrP) promoter elements, directing transgene expression predominantly to CNS neurons. The Mo/HuAPP695swe transgene expresses a "humanized" mouse amyloid beta (A4) precursor protein gene modified at three amino acids to reflect the human residues and further modified to contain the K595N/M596L (otherwise known as K670N/M671L) mutations linked to familial Alzheimer's. The PS1-dE9 transgene expresses a mutant human presenilin 1 carrying the exon-9-deleted variant (PSEN1dE9) associated with familial Alzheimer's disease. These constructs were coinjected into B6C3HF2 pronuclei and insertion of the transgenes occured at a single locus. Founder line 85 was obtained and the resulting colony was maintained as a hemizygote by crossing transgenic mice to B6C3F1/J mice. Transgenic mice were then backcrossed to C57BL/6J for at least 8 generations - see RRID:MMRRC_034832-JAX [The Jackson Laboratory Stock No. 005864].

In Jackson et al. 2015 PLoS One 10:e0125897, mice obtained from RRID:MMRRC_034832-JAX [The Jackson Laboratory Stock No. 005864] were found to have the APPswe and PSEN1de9 transgenes inserted at a single locus on chromosome 9 ~113 Mb [GRCm38]. The insertion site is a relative gene desert; ~600 kb distal to the Arpp1 gene and ~400 kb proximal to the Pdcd6ip gene. Both transgenes inserted at a single locus causing a 1 bp duplication [MGI:3524957].

In 2016, The Jackson Laboratory commissioned additional transgene analyses on spleen samples from RRID:MMRRC_034832-JAX [The Jackson Laboratory Stock No. 005864] hemizygous mice. This report concluded >20 transgene copies integrated on chromosome 9 ~113 Mb [mouse mm10], and suggested that some integration site sequence is likely duplicated [Chr9:113,003,660-113,021,621; mouse mm10].

Allele

Symbol: Tg(APPswe,PSEN1dE9)85Dbo
Name: transgene insertion 85, David R Borchelt
MGI accession ID: MGI:3524957
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: 2xTg Ad; APdE9; APP/PS1; APP-PS1; APPswe/PS1dE9; APPswe/PS1deltaE9; Mo/Hu APPswe PS1dE9
Marker symbol: Tg(APPswe,PSEN1dE9)85Dbo
Marker name: transgene insertion 85, David R Borchelt
Marker synonyms: APdE9; APP/PS1; APPswe/PS1dE9; Mo/Hu APPswe PS1dE9
Chromosome: 9
Strain of origin: (C57BL/6 x C3H)F2
Expressed genes: APP,amyloid beta precursor protein,human; PSEN1,presenilin 1,human
Site of expression: Co-injected transgenes encoding a chimeric mouse/human amyloid precursor protein (Mo/HuAPP695swe) and a mutant human presenilin 1 (PS1-dE9), both have independent mouse prion protein (PrP) promoter elements directing expression predominantly to CNS neurons.
Molecular note: Two transgenes inserted at a single locus in Chromosome 9 between Arpp21 and Pdcd6ip. Each transgene is controlled by the mouse prion promoter and contains a cDNA sequence. In one transgene the cDNA encodes a chimeric amyloid beta (A4) precursor protein (APPswe). In the second transgene the cDNA encodes the "DeltaE9" mutation of human presenilin 1. The DeltaE9 mutation of the human presenilin 1 gene is a deletion of exon 9 and corresponds to a form of early-onset Alzheimer's disease. The amyloid beta precursor protein coding sequences were altered by replacing mouse sequence encoding three amino acids of the A-beta domain with the human coding sequence for these residues. The chimeric amyloid beta (A4) precursor protein sequence was then further modified to encode the Swedish mutations K595N/M596L found in human. Both the transgenic peptide and holoprotein are detected by Signet Laboratories' monoclonal 6E10 antibody, which is specific for human sequence within this region. Human presenilin protein, which in high levels displaces detectable endogenous mouse protein, is immunodetected in the double transgenic mouse in whole brain protein homogenates. Human amyloid precursor protein is also immunodetected in these mice in whole brain protein homogenates. Transgene insertion occurred on Chr 9, causing a 1 bp duplication.
General note: Mice carrying this double transgene develop beta-amyloid deposits in the brain by 6 to 7 months of age.

Allele

Symbol: App^tm1Dbo
Name: targeted mutation 1, David R Borchelt
MGI accession ID: MGI:2136847
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: App-
Marker symbol: App
Marker name: amyloid beta (A4) precursor protein
Marker synonyms: AAA; Abeta; ABPP; AD1; Adap; alpha-sAPP; APPI; appican; betaAPP; CTFgamma; Cvap; E030013M08Rik; PN2; PN-II; preA4; protease nexin II
Chromosome: 16
Strain of origin: 129S7/SvEvBrd-Hprt1^b-m2
Molecular note: A neomycin resistance cassette replaced a 3.8 kb sequence including the promoter region and first exon. Northern blot analysis did not detect mRNA in brain or kidney of homozygous mutant mice.