PML is required for Tax sumoylation and degradation. (A) (upper) Endogenous Tax-PML interactions detected by Duolink in HuT-102 cells treated as indicated. PML was stained with anti-PML antibodies (green), and nuclei were stained with DAPI (blue). In the quantification below, significant P values are indicated by asterisks compared with untreated samples. (B) (upper) HuT-102 cells were transduced with nontargeting control shRNA (shCTRL) or shRNA against PML (shPML) and treated with AS/IFN for up to 48 hours. Degradation of endogenous Tax was analyzed by western blot. (Lower) HeLa cells transiently expressing Tax were treated as above. Percentages show quantification of remaining Tax at each time point after normalization to actin. (C) Tax-transfected HeLa-SUMO2 cells were cotransfected with either siCTRL or siPML. Tax immunoprecipitates (IP: Tax) were blotted against SUMO2/3 and Tax. Arrow points to the band corresponding to Tax, whereas asterisk denotes IgG heavy chain. First lane shows control IP with no antibody.