P97 is recruited to PML bodies in response to arsenic. U2OS PML^−/− + YFP-PML cells were treated with arsenic for the times indicated, pre-extracted as described in Materials and methods, fixed, and stained with an antibody to p97. (A) Images of p97 (green), YFP-PML (red), and DAPI (blue) are shown. Scale bars are 10 μm. (B) The percentage of PML bodies colocalized with p97 was plotted against time of arsenic treatment. Chart shows individual cell data. Bars represent mean with SEM. P values are two-tailed Mann-Whitney U test derived by comparison with untreated. Cell count n = 41 (untreated), n = 38 (2 h), n = 38 (4 h), and n = 25 (6 h). (C) WT U2OS cells or PML^−/− + YFP-PML U2OS cells were transfected with plasmids expressing myc-p97 constructs of either WT or E578Q mutant form and either treated or not with 1 μM arsenic for 6 h. Nuclear extracts (Input) or YFP-PML purifications (Pulldown) were blotted for PML or Myc. Molecular weight markers are indicated in kD. Source data are available for this figure: SourceData F4.