Staining for wild-type and hybrid PML proteins.

(A) Speckled nuclear staining, representing wild-type PML, in transfected U937 cells (left) and in a case of FAB-M5 acute leukemia (right). (B) Nuclear microspeckled staining pattern indicating the presence of hybrid PML-RARα protein in 2 cases of APL. Single arrows indicate normal residual marrow cells; and arrowhead, a red blood cell (APAAP and immunofluorescent techniques in cytospin preparations; reproduced with permission from Blood177). (C) Laser-scan confocal microscopy of the KG1 myeloid cell line double stained for PML (green) and PLZF (red). At left is the confocal image. At right is a 3-dimensional reconstruction of the area outlined on the left panel, showing the spatial relation between PML and PLZF in the nuclear bodies. Original magnification A-C, × 1000.