Exons 10-12 (from codon I264 in exon 10 to codon V340 in exon 12) of the mouse were replaced with the corresponding human exons of 10-12 which comprise the critical Middle East respiratory syndrome coronavirus (MERS-CoV) receptor. A neomycin resistance gene flanked by FRT sites and a puromycin resistance gene flanked by F3 sites were inserted in intron 9 and intron 12, respectively. The selection markers were removed via Flp-mediated recombination. (J:242025)