In addition to responding to HCMV, increased luciferase expression upon infection of NIH3T3 cells with mouse cytomegalovirus (MCMV) was evident in a virus dose-dependent manner with both constructs (with or without an IFN-inducible promoter element), while only baseline luciferase expression was seen in mock infected cells (data not shown). The gene discussed is IFNA1; the disease is infection.