STOCK Apoe^tm1Unc Tg(APOE3*R224Q)1Her/J

Stock number: 029818
Product name: bEKO
Strain synonyms: bEKO
Research areas: Cardiovascular Research, Metabolism Research, Mouse/Human Gene Homologs, Neurobiology Research, Research Tools

Description

These bEKO (brain ApoE knock-out) mice carry a knock-out allele of Apoe and a transgene containing mutant R224Q human APOE sequence, and express the APOE protein in peripheral tissues but with significantly reduced expression in the brain. These mice may be suitable for use in studies related to Alzheimer's disease.

Detailed description

The APOE Ε4 (ApoE4) allele is the strongest genetic risk factor for developing late onset Alzheimer's disease, and also increases the risk of dementia with Lewy bodies. These bEKO knock-out/transgenic mice express the mutant human R224Q human APOE in peripheral tissues, with significantly reduced expression in the brain. The transgene integration site confers the expression pattern of the R224Q APOE to peripheral tissues. Substantially reduced expression of APOE protein is detected by western blot of hippocampal brain tissue from bEKO mice. While synapatic loss and LTP reduction in bEKO mice is similar to that observed in ApoE knock-out mice, bEKO mice do not exhibit spatial learning impairment. Mice that are homozygous for the targeted mutation allele and transgene are viable and fertile. The Donating Investigator reports that mice hemizygous for the transgene and homozygous for the Apoe knock-out allele exhibit plasma lipid levels similar to that of wildtype controls.

Development

A transgenic construct containing sequences coding for human APOE3, with the R224Q mutation, was injected into fertilized B6;129 mouse eggs. Founder line 1 was subsequently established. The mice were bred to homozygosity for the transgene. Homozygous transgenic mice were then bred to Apoe knock-out mice (Stock No. 002052) The mice were maintained on a mixed B6;129 background.

Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664). The mice were then bred to homozygosity for both the transgene and targeted mutation allele.

Allele

Symbol: Tg(APOE3*R224Q)1Her
Name: transgene insertion 1, Joachim Herz
MGI accession ID: MGI:5927758
Generation method: Transgenic
Attributes: Inserted expressed sequence; Humanized sequence
Synonyms: Tg(APOE3*R224Q)1Her
Marker symbol: Tg(APOE3*R224Q)1Her
Marker name: transgene insertion 1, Joachim Herz
Chromosome: UN
Strain of origin: 129 or C57BL/6
Expressed genes: APOE,apolipoprotein E,human
Site of expression: Peripheral tissue plasma.
Molecular note: This transgene resulted from random integration of a human APOE expression cassette encoding the E3 variant with an inadvertent mutation resulting in replacement of arginine by glutamine at amino acid position 224 (p.R224Q). The transgenic construct contained a mouse/human chimeric gene comprising 5.3 kb of strain 129 mouse genomic DNA upstream of the Apoe coding region, including exon 1 and the 5' 376 bp of intron 1; most of the human APOE3 variant allele, including the 3' 723 bp of intron 1, exons 2-4 containing the entire protein coding region, and 1.5 kb of 3'-flanking DNA; a neomycin resistance cassette; and a 1.4-kb mouse genomic fragment containing the 3' part of exon 4 and 3' flanking DNA. This construct was introduced into B6;129 fertilized oocytes. Western blot analysis of plasma and of liver lysates revealed similar levels of endogenous APOE protein in wild-type mice and of human APOE in mice homozygous for both the transgene and a null allele of Apoe (Apoe^tm1Unc), but hippocampal lysates from the latter mice contained barely detectable levels of human APOE; immunohistochemical analysis of hippocampal sections of transgenic/knockout brains using an anti-APOE antibody showed faint, diffuse interstitial staining, but no staining of cells. Thus, transgene-derived human APOE is expressed normally in the periphery, but is essentially absent in the brain.

Allele

Symbol: Apoe^tm1Unc
Name: targeted mutation 1, University of North Carolina
MGI accession ID: MGI:1857129
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: AopE(-); apoE-; APOE KO; Apoe^tm1Un; apoE0; ApoE-KO; EKO; epsilon-; mE^-; mEKO
Marker symbol: Apoe
Marker name: apolipoprotein E
Marker synonyms: AD2; APO-E; ApoE4; APOEA; LDLCQ5; LPG
Chromosome: 7
Strain of origin: 129P2/OlaHsd
Molecular note: Insertion of a neomycin resistance cassette deleted part of exon 3 and part of intron 3 of the Apoe gene. Plasma from homozygous mutant mice gave no detectable immunoprecipitate by the Ouchterlony double immunodiffusion test using a rabbit antibody to rat APOE.