Although neither infection with wt nor ICP0-deficient HSV-1 is enhanced in the absence of PML in PML–/– murine embryonic fibroblasts (MEFs) compared to control PML+/+ MEFs, the replication of the ICP0-deletion virus is substantially compromised by IFN treatment of these cells in the presence but not absence of PML [100]. The gene discussed is PML; the disease is infection.