B6J.B6N(CBA)-Isr(HSA17)1Mdk Psen1^{tm1.1(PSEN1)Mdk} App^{tm1.1(APP)Mdk}/J

Stock number: 039175
Product name: P₁A_τ (3X-GR)
Strain synonyms: MAPT-GR wt(H2.1); PSEN1-GR wt; APP-GR wt, B6J.B6N(CBA)-Tc(HSA17)1Mdk Psen1^{tm1.1(PSEN1)Mdk} App^{tm1.1(APP)Mdk}/J
Research areas: Mouse/Human Gene Homologs, Neurobiology Research

Description

This strain was created by combining the following alleles: Isr(HSA17)1Mdk (MAPT[H2.1]-GR) Stock No. 033668, Psen1^{tm1.1(PSEN1)Mdk} (PSEN1-GR wt) Stock No. 039177, App^{tm1.1(APP)Mdk} (APP-GR wt) Stock No. 038920.

The combination creates a humanized knock-in/knock-out that has human genes replacing mouse genes at the Psen1 and App loci, as well as expressing the human MAPT (H2 haplotype) and MAPT-AS1 transcripts and the typical MAPT protein isoforms. This strain may serve as base model into which additional alterations can be introduced to explore more fully the role of the PSEN1, APP and MAPT in Alzheimer's disease (AD).

Detailed description

This strain was created by combining the following alleles: Isr(HSA17)1Mdk (MAPT[H2.1]-GR) Stock No. 033668, Psen1^{tm1.1(PSEN1)Mdk} (PSEN1-GR wt) Stock No. 039177, App^{tm1.1(APP)Mdk} (APP-GR wt) Stock No. 038920.

The interspecies replacement (Isr) MAPT(H2.1)-GR (Gene Replacement) mice contain a syntenic 190 kb region from human chromosome 17 (HSA17) that includes SPPLC2 (signal peptide peptidase 2C) and MAPT (microtubule-associated protein tau), specifically the H2 haplotype. The region replaces ~157 kb on mouse chromosome 11 stretching from, but not including, Crhr1 to Kansl1. The SPPL2C sequence is included because it is embedded entirely in the MAPT-AS1 transcribed region. Human MAPT (microtubule-associated protein tau) is found within a 900 kb inversion on Chr 17q21 that defines two haplotypes, H1 and H2, found in Caucasians. H2 is associated with decreased risk of late onset AD, and lower MAPT levels in the cerebellum and temporal cortex.

Presenilin 1 is the catalytic subunit of the gamma-secretase complex which cleaves beta-amyloid precursor protein and NOTCH receptor proteins. These humanized Psen1 knock-in/knock-out mice carry a 106 kb fragment of human PSEN1 replacing the mouse Psen1 locus.

Amyloid beta (A4) precursor protein (APP) is a type I integral membrane protein that is cleaved to form a number of peptides, in particular, the amyloid-β-peptide, a component of the amyloid plaques associated with Alzheimer's disease. These humanized App knock-in/knock-out mice carry a 350 kb fragment of human APP replacing the mouse App locus.

Mice homozygous for the three alleles are viable and fertile.

Development

This strain was created by combining the following alleles: Isr(HSA17)1Mdk (MAPT[H2.1]-GR) Stock No. 033668, Psen1^{tm1.1(PSEN1)Mdk} (PSEN1-GR wt) Stock No. 039177, App^{tm1.1(APP)Mdk} (APP-GR wt) Stock No. 038920.

The MAPT-GR wt(H2.1) targeting event is designed to insert a syntenic 190.5 kb region from human chromosome 17 (HSA17; Chr17:45,838,648-46,029,144) in place of a 156.5 kb of mouse chromosome 11 (Chr11:104,066,949-104,223,491) stretching from, but not including, Crhr1 to Kansl1. The genomic sequences are from mouse assembly GRCm39 and human assembly GRCh38.p14 [PMID:38343132 Benzow et al., 2024 Alzheimers Dement. 20:3080]. In this transchromosomal (Tc) strain, the mouse Sppl2c (signal peptide peptidase 2C) and Mapt (microtubule-associated protein tau) genes are replaced by human SPPL2C and MAPT (H2 haplotype) genes. The deletion/insertion was made using C57BL/6N-PRX-B6N embryonic stem cells (ES) and loxN-flanked hygromycin resistance cassette. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were crossed to B6.Cg-Edil3^{Tg(Sox2-cre)1Amc}/J (Stock No. 008454) to remove the hygro cassette and then backcrossed to C57BL/6J for at least 5 generations.

The PSEN1-GR wt targeting vector is designed to insert a 106 kb (Chr14:73,121,400-73,227,703) fragment of the human PSEN1 (presenilin 1) in place of Chr12:83,730,110-83,793,335 of the mouse Psen1 gene on chromosome 12. The construct included loxP-flanked neomycin selection cassette. In addition, there is also a PSEN1-DT (non-coding antisense RNA) in the human genome segment. The insertion disrupts PSen1 transcription. The construct was electroporated into C57BL/6N-PRX-B6N embryonic stem cells (ES). The neomycin cassette was removed by transient expression of Cre. Correctly targeted ES cells were injected into blastocysts. Chimeric animals were backcrossed to C57BL/6J mice for at least 5 generations.

The APP-GR wt targeting vector is designed to insert a 343 kb (Chr21:25,880,264-26,224,036) fragment of the human APP (apolipoprotein) in place of 268 kb (Chr16:84,750,107-85,019,011) of the mouse App gene on chromosome 16. The construct included a loxP-flanked neomycin selection cassette. In addition, there is also a APP-DT (non-coding antisense RNA) in the human genome segment. The insertion disrupts App transcription. The construct was electroporated into C57BL/6N-PRX-B6N embryonic stem cells (ES). The neomycin cassette was removed by transient expression of Cre. Correctly targeted ES cells were injected into blastocysts. Chimeric animals were backcrossed to C57BL/6J mice for at least 5 generations.

Upon arrival at The Jackson Laboratory Repository in 2024, the strain was cryopreserved as embryos.

The genomic sequences are from human assembly GRCh38.p14 and the mouse assembly GRCm39.

Allele

Symbol: App^{tm1.1(APP)Mdk}
Name: targeted mutation 1.1, Michael D Koob
MGI accession ID: MGI:7565473
Generation method: Targeted
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: APP-GR
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: C57BL/6NTac
Molecular note: The targeting vector is designed to insert a 343 kb (Chr21:25880264 - 26224036) fragment of the human APP (apolipoprotein) in place of 268 kb (Chr16:84750107 - 85019011) of the mouse App gene. The construct includes an FRT-flanked neomycin selection cassette. In addition, there is also a APP-DT (non-coding antisense RNA) in the human genome segment. The insertion disrupts App transcription.The neomycin cassette was removed by transient expression of cre.

Allele

Symbol: Psen1^{tm1.1(PSEN1)Mdk}
Name: targeted mutation 1.1, Michael D Koob
MGI accession ID: MGI:7576962
Generation method: Targeted
Attributes: Null/Knockout; Inserted expressed sequence; Humanized sequence
Synonyms: PSEN1-GR
Marker symbol: Psen1
Marker name: presenilin 1
Marker synonyms: ACNINV3; AD3; Ad3h; CMD1U; FAD; presenilin-1; PS1; PS-1; PSNL1; S182
Chromosome: 12
Strain of origin: C57BL/6NTac
Molecular note: The targeting vector is designed to insert a 106 kb (Chr14:73121400 - 73227703) fragment of the human PSEN1 in place of Chr12:83730110 - 83793335 of the mouse Psen1 gene. The construct includes a loxP-flanked neomycin selection cassette. In addition, there is also a PSEN1-DT (non-coding antisense RNA) in the human genome segment. The insertion disrupts Psen1 transcription. The neomycin cassette was removed by transient expression of Cre.

Allele

Symbol: Isr(HSA17)1Mdk
Name: interspecies replacement, human Chr 17, Michael Koob 1
MGI accession ID: MGI:6363617
Generation method: Targeted
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: MAPT-GR; Tc(HSA17)1Mdk
Marker symbol: Isr(HSA17)1Mdk
Marker name: interspecies replacement, human Chr 17, Michael Koob 1
Marker synonyms: Tc(HSA17)1Mdk
Chromosome: 11
Strain of origin: C57BL/6NTac
Site of expression: neurons of the central nervous system and at low levels in astrocytes and oligodentrocytes

Molecular note: A 157 kb deletion on mouse Chromosome 11 stretching from, but not including, Crhr1 to Kansl1 is replaced by a syntenic 190 kb region from human Chromosome 17 (HSA17). In this interspecies replacement (Isr) strain, the mouse Sppl2c (signal peptide peptidase 2C) and Mapt (microtubule-associated protein tau) genes are replaced by human SPPL2C and MAPT genes and a loxN-flanked hygromycin cassette. Cre-mediated recombination removed the hygromycin cassette.