B6;129-Apba2^tm1Sud Apba3^tm1Sud Apba1^tm1Sud/J

Stock number: 006394
Product name: Mint triple-floxed
Research areas: Neurobiology Research, Research Tools

Description

These Mint triple-floxed mice may be useful for generating conditional mutations in applications relating to neurotransmission.

Detailed description

Triple homozygous knock-in mice are viable and fertile and and do not display any gross physical or behavioral abnormalities. Expression of all three proteins is normal. When crossed with a cre deleter strain that eradicates protein expression, Apba1/Abcba2 (Apba1/2) double knockout and Apba1/2/3 triple knockout mice exhibit a high percentage of postnatal lethality (only ~20% of the mice survive). Apba1/2 mice are visually indistinguishable from their littermates and display no major alterations in breathing, movements or reaction to stimuli several hours after birth, but fail to nurse and die within 24 hours. Their brains are morphologically and structurally normal. Quantitation of 18 neuronal proteins fails to reveal significant changes. Surviving mice show reduced weight gain and exhibit movement dysfunction. Cultured neurons from triple knock-in neonates show impairments in presynaptic neurotransmitter release after treatment with lentiviral cre. Apba1/3 and Apba2/3 double knockouts created from crosses with a cre deleter strain survive normally.

Development

loxP sites flanking the first coding exon of Apba1, residues 368-416 of the Apba2, and exon 3 of Apba3 (encoding residues 201-249) were incorporated into three targeting vectors which also contained Frt-flanked neomycin resistance cassettes inserted into the respective downstream (Apba1 and Apba2) or upstream (Apba3) introns. The constructs were independently electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells. The neomycin cassettes were subsequently excised from all but the Apba1 mutant strain in which the drug selection cassette does not interfere with expression. Compound mutant mice were generated by intercrossing the individual mutant lines.

Allele

Symbol: Apba1^tm1Sud
Name: targeted mutation 1, Thomas C Sudhof
MGI accession ID: MGI:3697697
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Apba1
Marker name: amyloid beta (A4) precursor protein binding, family A, member 1
Chromosome: 19
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: Flanking loxP sites were introduced to exon 1 and an frt-flanked neomycin resistance cassette was inserted into the downstream intron via homologous recombination.

Allele

Symbol: Apba3^tm1Sud
Name: targeted mutation 1, Thomas C Sudhof
MGI accession ID: MGI:3697711
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Apba3
Marker name: amyloid beta (A4) precursor protein-binding, family A, member 3
Chromosome: 10
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: Exon 3, encoding amino acids 201-249 of the phosphotyrosine binding (PTB) domain, is flanked by loxP sites. A single FRT site, the remnant of an FRT-flanked neomycin resistance cassette (neo) previously removed by crossing mice with the cassette to mice expressing Flp recombinase in the germline, is present in the downstream intron. (Retention of the neo cassette ablates expression of this gene in mice.) Immunoblot analysis of brain homogenates demonstrates that mice with this conditional mutation express the protein at wild-type levels.

Allele

Symbol: Apba2^tm1Sud
Name: targeted mutation 1, Thomas C Sudhof
MGI accession ID: MGI:3697709
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Apba2
Marker name: amyloid beta (A4) precursor protein-binding, family A, member 2
Chromosome: 7
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: The exon encoding amino acids 368-416 of the phosphotyrosine binding (PTB) domain is flanked by loxP sites. A single FRT site, the remnant of an FRT-flanked neomycin resistance cassette (neo) previously removed by crossing mice with the cassette to mice expressing Flp recombinase in the germline, is present in the downstream intron. (Retention of the neo cassette ablates expression of this gene in mice.) Immunoblot analysis of brain homogenates demonstrates that mice with this conditional mutation express the protein at wild-type levels.