C57BL/6J-Apoe^{em10(APOE*)Msasn}/J

Stock number: 038052
Product name: APOE3s2
Research areas: Cancer Research, Mouse/Human Gene Homologs, Neurobiology Research, Research Tools

Description

APOE3s2 humanized knock-in mice carry a modified human APOE3 exons 2-4 inserted into the mouse Apoe (apolipoprotein E) locus where exon 4 (APOE3) is floxed and, upon exposure to Cre recombinase, swapped for a codon optimized exon 4 (APOE2). Exon 4 (APOE3) is then deleted. This strain maybe be useful for in studies of Alzheimer's disease.

Detailed description

The targeted Apoe gene encodes apolipoprotein E, which is important in lipoprotein metabolism and cardiovascular disease as well as Alzheimer's disease, immunoregulation and cognition. The primary function of APOE in the brain is to transport cholesterol. Human APOE contains 4 exons, with the coding region beginning in exon 2; exon 4 codes for 80% of the protein and contains the LDLR and lipid binding regions. APOE3s2 humanized knock-in mice were created using CRISPR/cas9 genome editing to insert human APOE3 exons 2-4 into the mouse Apoe locus using a conditional by inversion (COIN) cassette containing the APOE3 sequence with a loxP-flanked exon 4 followed by a lox2272-flanked APOE2 exon 4 in reverse orientation. Upon exposure to Cre recombinase the APOE3 exon 4 is deleted and APOE2 exon 4 is inverted and transcribed. Mice heterozygous for the mutation are viable and fertile. The donating investigator has not attempted to generate homozygotes. As the mice are characterized, we will modify the strain description and add phenotype data.

Development

APOE3s2 is a CRISPR/Cas9-generated mutant in the apolipoprotein E (Apoe) gene on Chromosome 7 that contains a conditional by inversion (COIN) cassette containing APOE3 human genomic sequence exons 2-4 with and 1500bp of the 3' UTR. The APOE3 sequence contains a loxP site downstream of exon 3, a polyA signal downstream of exon 4, followed by a lox2272 site APOE2 exon 4 in reverse orientation, a loxP site and a lox2272 site followed by the APOE3 3' UTR. Double-stranded plasmid DNA, Cas9 mRNA, and sgRNA guide sequences were introduced into C57BL/6J zygotes via pronuclear injection. The founder was backcrossed to C57BL/6J mice (Stock No. 000664) and sperm was cryopreserved from heterozygous males at generation N2 (see SNP note below).

In 2025, a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the males sent to The Jackson Laboratory Repository. One of the 43 markers throughout the genome was segregating with an unknown source.

Allele

Symbol: Apoe^{em10(APOE*)Msasn}
Name: endonuclease-mediated mutation 10, Michael Sasner
MGI accession ID: MGI:7581969
Generation method: Endonuclease-mediated
Attributes: Conditional ready (e.g. floxed); Humanized sequence
Synonyms: APOE3s2
Marker symbol: Apoe
Marker name: apolipoprotein E
Marker synonyms: AD2; APO-E; ApoE4; APOEA; LDLCQ5; LPG
Chromosome: 7
Strain of origin: C57BL/6J
Molecular note: CRISPR/cas9 inserted sequences into the apolipoprotein E (Apoe) gene on chromosome 7 that contains a conditional by inversion (COIN) cassette containing APOE3 human genomic sequence exons 2-4 with and 1500bp of the 3' UTR. The APOE3 sequence contains a loxP site downstream of exon 3, a polyA signal downstream of exon 4, followed by a lox2272 site APOE2 exon 4 in reverse orientation, a loxP site and a lox2272 site followed by the APOE3 3' UTR.