The results of immunoblot analysis showed that IE1 overexpression suppressed the induction of ISG15 and ISG15 conjugates by both virus infection and IFNβ treatment (as a control) (Fig 2C, compare lanes 2–5 and 7–10), further supporting the critical role of IE1 in reducing ISG15 expression. The gene discussed is IFNB1; the disease is viral infectious disease.