STOCK Antxr1^tm1.2Lepp/J

Stock number: 027705
Product name: TEM8^-
Research areas: Research Tools

Description

TEM8^-/- mice may be useful for studying Bacillus anthracis (anthrax) pathogenesis.

Detailed description

TEM8^-/- mice lack exon 13, encoding the transmembrane domain of the anthrax toxin receptor 1 (Antxr1) gene. TEM8 is one of two Bacillus anthracis (anthrax) toxin receptors. It contains a signal peptide, an extracellular von Willebrand factor A (VWA) domain, a transmembrane domain, and a cytosolic tail. Anthrax toxin protective antigen, the receptor binding moiety of anthrax toxins, has an 11-fold lower affinity for TEM8 than for its other receptor, CMG2 (anthrax toxin receptor 2 (Antxr2). TEM8 is also involved in extracellular matrix adhesion, migration, and signal transduction. Mice that are homozygous for this are viable, however the donating investigator reports that homozygous KO females are infertile. These TEM8^-/- mice lack the transmembrane domain of TEM8. These mice produces a high level of soluble (secreted extracellular domain) TEM8 due to disruption of only the cell surface form. These mice show similar sensitivity to a lethal dose of anthrax lethal toxin as control mice, with 90% of these mice succumbing within 2 weeks of infection.

When bred to mice lacking CMG2 (anthrax toxin receptor 2 (Antxr2)) (available with a floxed allele, see Stock No. 027703), resulting double KO mice are completely resistant to anthrax toxin.

Development

A targeting vector was designed to insert a loxP site upstream of exon 13, and a frt-flanked neomycin resistance (neo) cassette, followed by second loxP site, downstream of exon 13 of the anthrax toxin receptor 1 (Antxr1) gene. The construct was electroporated into 129S1/Sv-Oca2⁺ Tyr⁺ Kitl⁺-derived W9.5 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and resulting chimeric males were bred to C57BL/6J females. Offspring were bred with Cre Recombinase expressing mice on a C57BL/6J background to delete the neo cassette and exon 13, and progeny were crossed to remove the cre-expressing transgene. These mice were maintained on a mixed background. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Antxr1^tm1.2Lepp
Name: targeted mutation 1.2, Stephen H Leppla
MGI accession ID: MGI:4352941
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: TEM8^-
Marker symbol: Antxr1
Marker name: anthrax toxin receptor 1
Marker synonyms: 2310008J16Rik; 2810405N18Rik; ATR; GAPO; TEM8
Chromosome: 6
Strain of origin: 129S1/Sv-Oca2⁺ Tyr⁺ Kitl⁺
Molecular note: A loxP site was inserted upstream of exon 13, which encodes the transmembrane domain, and an frt flanked neo cassette and second loxP site were inserted downstream of exon 13. Cre mediated recombination then removed exon 13 l and (when present) the neo cassette leaving behind a single loxP site. Western blot analysis confirmed the absence of protein expression in lysates from homozygous MEFs but a mutant protein was detected in conditioned media from homozygous MEFs.