Varying cellular localization of mutant PML-RARA upon As₂O₃ treatment compared with wild-type. Representative immunofluorescence analysis for Flag-tagged wild-type (A) and mutant (B-F) PML-RARA expressed in HeLa cells, with or without As₂O₃ treatment (1 μM, 16 hours). The staining of Flag is shown in red. 4,6 diamidino-2-phenylindole (DAPI) is shown in blue.