The Art2a and Art2b genes were disrupted via homologous recombination in 129S4/SvJae-derived J1 ES cells. Most of exon 3, the major coding exon, of Art2a was replaced with a neomycin resistance cassette and this Art2atm1Fkn-bearing cell line was then transfected with a construct which replaced most of the major coding exon of Art2b with a hygromycin resistance cassette. The resulting ES cell with two targeted mutations was injected into blastocysts and a resulting founder was bred once with C57BL/6J and the offspring were intercrossed. F3 mice were sent from Dr. Nigel Killeen to Dr. Edward Leiter at The Jackson Laboratory and backcrossed onto the NOD/Lt background. In 2004 this strain reached N7F2.
