B6;129S7-Apob^tm2Sgy/J

Stock number: 002877
Product name: apo-B¹⁰⁰
Research areas: Cardiovascular Research, Developmental Biology Research, Mouse/Human Gene Homologs, Neurobiology Research

Description

Homozygous apo-B¹⁰⁰ knock-out mice exhibit low HDL cholesterol.

See Updated Apob Allele Information below [2020].

Detailed description

Apo-B¹⁰⁰ homozygous mice express only the Apo-B100 isoform of the mouse Apob (apolipoprotein B) gene and exhibit low HDL cholesterol. See Updated Apob Allele Information below.

A CTA to TTA mutation was introduced to sequences corresponding to the apo-B48 editing codon (codon 2179; codon 2153 in the original publication, PMID: 8692825) in exon 26. Western blot analysis on plasma derived from heterozygous and homozygous mice demonstrates that the expression of the Apo-B100 isoform is unaffected by this mutation, while no Apo-B48 isoform is produced from this allele.

Their development is normal and there are no intestinal abnormalities. LDL cholesterol is normal. Homozygotes have lower HDL cholesterol levels than either wildtype or APOB48-expressing mice (see Stock No. 002876).

Updated Apob Allele Information: In 2020, analysis by The Jackson Laboratory determined the mice to have the post-FIAU Apo-B¹⁰⁰ (the neo, TK and duplicate exons 26-29 deleted) allele on one homologous chromosome, and pre-FIAU Apo-B¹⁰⁰ (retaining the neo, TK and duplicate exons 26-29) on the other homologous chromosome. This analysis also confirmed that RT-PCR of compound heterozygous liver shows predicted change in coding component (CAA to CTA in codon 2179), and reduced HDL was verified (64.2 mg/dL +/- 9.02 [n=9] compared to C57BL/6J 94.9 mg/dL +/-6.5 [n=4]).

Development

A "hit and run"-type vector was used to create a CTA to TTA mutation in codon 2179 (codon 2153 in the original publication) sequences corresponding to the apo-B48 editing codon in exon 26 of the mouse Apob gene. The mutation was created through homologous recombination in 129S7/SvEvBrd-Hprt⁺-derived embryonic stem (ES) cells. Western blot analysis on plasma derived from heterozygous and homozygous mice demonstrates that the expression of the ApoB100 isoform is unaffected by this mutation, while no ApoB48 isoform is produced from this allele.

The original publication (Farese et al. 1996 Proc Natl Acad Sci U S A. 93:6393 [PMID:8692825]) indicates in vitro treatment with 1-[2-fluoro-13-D-arabinofuranosyl]-5-iodouracil (Fialuridine [FIAU]) was performed in an effort to delete the 3' targeting vector sequences (neo, thymidine kinase, and duplicate exons 26-29) - see Updated Apob Allele Information below.

Updated Apob Allele Information: In 2020, analysis by The Jackson Laboratory determined the mice to have the post-FIAU Apo-B¹⁰⁰ (the neo, TK and duplicate exons 26-29 deleted) allele on one homologous chromosome, and pre-FIAU Apo-B¹⁰⁰ (retaining the neo, TK and duplicate exons 26-29) on the other homologous chromosome. This analysis also confirmed that RT-PCR of compound heterozygous liver shows predicted change in coding component (CAA to CTA in codon 2179), and reduced HDL was verified (64.2 mg/dL +/- 9.02 [n=9] compared to C57BL/6J 94.9 mg/dL +/-6.5 [n=4]).

Allele

Symbol: Apob^tm2Sgy
Name: targeted mutation 2, Stephen G Young
MGI accession ID: MGI:1857304
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: ApoB¹⁰⁰; apo-B¹⁰⁰; ApoB^100only; ApoB48^-
Marker symbol: Apob
Marker name: apolipoprotein B
Marker synonyms: Aa1064; Ac1-060; Apo B-100; apob-100; apob-48; FCHL2; FLDB; LDLCQ4
Chromosome: 12
Strain of origin: 129S7/SvEvBrd-Hprt1⁺
Site of expression: Expression of the ApoB100 isoform is unaffected by this mutation, while no ApoB48 isoform, which is normally synthesized by the small intestine, is produced from this allele.
Molecular note: A "hit and run"-type vector was used to create a CTA to TTA mutation in codon 2179 (codon 2153 in the original publication) in sequences corresponding to the apo-B48 editing codon. Western blot analysis on plasma derived from heterozygous and homozygous mice demostrated that the expression of the ApoB100 isoform is unaffected by this mutation, while no ApoB48 isoform is produced from this allele.
General note: Levels of LDL-cholesterol, VLDL, and triglyceride LDL are higher relative to wild-type mice in APOB100 only mice in the presence of wild-type APOE production. In the presence of genetic APOE deficiency, APOB100 only mice have lowered cholesterol levels (J:33830).

Phenotypic Similarity to Human Syndrome: Calcific Aortic Valve Disease J:227165 in mice homozygous for Apob^tm2Sgy and Ldlr^tm1Her and carrying the Tg(Ins-Igf2)1Fbos transgene.