Importantly, ATRX, DAXX, H3.3, and promyelocytic leukaemia (PML) nuclear bodies (PML-NBs) are responsible for the epigenetic silencing of transposable elements such as the endogenous retroviral elements (ERVs) in the mouse genome [10,17,18], as well as in the defence against viral infection [19,20,21]. The gene discussed is PML; the disease is viral infectious disease.