Figure 1

All PML protein isoforms form nuclear bodies in cells lacking endogenous PML. (A) Schematic depiction of the domain structure of PML isoforms (data taken from [16]). All PML isoforms share a common N terminus (exons 1 to 6) but differ in their C termini due to alternative spilicing of exons 7 to 9. Numbers indicate exons. Stars indicate retained intron sequences. The postion of three SUMO-modifyable Lysin (K) residues are indicated. Note that PML VI does not contain and the SUMO-interacting motiv (SIM) present in the other isoforms. (B) Mouse 3T3 cells with (3T3-PML^+/+) or without (3T3-PML^-/-) endogenous PML expression were transfested with expression vectors encoding human PML isoforms I to VI as GFP fusion proteins. Cells on coverslips were fixed and processed for immunofluorescence staining to detect endogenous mouse PML protein (red) and the exogenous GFP-tagged human PML isoforms (green). Images show mid-nuclear confocal sections. Note that the anti-mouse-PML antibody does not cross-react with human PML. Bar, 5 μm.