To develop a reliable model susceptible to MERS-CoV, stable transgenic mouse models expressing hDPP4 or mouse DPP4 edited through the CRISPR/Cas9 system to accommodate MERS-CoV infection were generated and, after which progressive pneumonia and lethal effects in the transgenic mice were confirmed following MERS-CoV infection [34, 35]. The gene discussed is DPP4; the disease is pneumonia.