CMG2flox/flox mice possess loxP sites flanking exon 12, encoding the transmembrane domain of the anthrax toxin receptor 2 (Antxr2) gene. CMG2 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 higher affinity for CMG2 than for its other receptor, TEM8 (anthrax toxin receptor 1 (Antxr1). CMG2 is also involved in extracellular matrix adhesion, migration, homing, pattern formation, and signal transduction. Mutations in the transmembrane domain of CMG2 have been associated with the onset of juvenile hyaline fibromatosis (JHF) and infantile systemic hyalinosis (ISH). Mice that are homozygous for this allele are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exon 12 deleted in the cre-expressing tissues.
When bred to ACTB-cre mice, with wide spread expression of Cre recombinase, CMG2-/- mice are highly resistant to both anthrax toxins as well as B. anthracis infection. When subsequently bred to mice lacking TEM8 (anthrax toxin receptor 1 (Antxr1)) (Stock No. 027705), resulting double KO mice are completely resistant to anthrax toxins.
