Fig. 2. Specific PML isoform C-terminus encodes a nucleolar targeting domain. (A) Plasmids encoding the various nls-GFP fusion proteins (top) were transfected into human osteosarcoma cells, SaOS, which were observed 24 hours later. GFP-PML fusion proteins appear in green, nucleolar markers UBF, fibrillarin, B23 and RNA (revealed by BET), in red. (B) The presence of a inhibitor domain SIM in the C-terminus of PML-I. Different PML-I C-terminal fragments are fused to nls-GFP to estimate their nucleolar targeting property. Results are reported in the diagram. (C,D) Characterization of the targeting of the PML-IV-specific terminus (C) and the PML-V-specific terminus (D). The PML sequence is indicated by the positions of the residues on the original isoforms. Staining as in A. (E) Amino acid sequences of the regions required for nucleolar association in PML-I (607-619 and 865-882), PML-IV (607-633) and PML-V (571-611).