Subcellular localization of NLS6-defective PML isoforms. A) Schematic of PML isoforms analyzed in the present study. Regions containing the RING domain (RING), B-boxes (B), Coiled-coil (CC), the nuclear localization signal encoded by exon 6 (NLS6), the SUMO interaction motif (SIM) and the PML I-specific nuclear export signal (NES) are shown. B) Representative images showing subcellular localization of His-tagged PML isoforms with or without a functional NLS6. His-tagged PML was visualized using anti-His antibodies. C) Overlay images showing fluorescently labelled His-tagged isoform (red) and phase contrast images (green). Magnifications show co-localization of PML and membrane enclosed vesicles. D) Endogenous PML in U2OS cells. Arrow points to PML at the nuclear periphery.