p97 cofactors UFD1 and NPLOC4 are required for arsenic-induced degradation of PML. U2OS PML^−/− + YFP-PML cells were treated with NT siRNA or siRNAs to p97 cofactors and exposed to arsenic. (A) Western blot analysis with antibodies to PML, p97 cofactors, or Lamin A/C. Molecular weight markers are indicated in kD. (B) Immunofluorescence analysis of YFP-PML in response to arsenic. Scale bars are 20 μm. (C) Time-lapse fluorescent imaging for 9.75 h after exposure to arsenic. 10 videos were collected for each condition (n = 10; example videos in Videos 5, 6, 7, 8, 9, and 10). Average relative PML body intensity per cell was plotted versus time. (D) Relative PML intensity per cell of cells treated with NT or siRNAs to p97 cofactors after 10 h arsenic (As) treatment. P values are comparisons with NT + As using two-tailed unpaired Student’s t test assuming similar deviations. Each data point is a single field of view taken from C (n = 10). Source data are available for this figure: SourceData F5.