PML and leukemia: To confirm that the GFP-His fusions almost completely co-localized with SC35 positive speckles, we carried out an immunofluorescence analysis with protein markers of other subnuclear compartments that are compatible with such staining, including promyelocytic leukemia (PML) bodies (for review, see [27]), Sumo-bodies (for review, see [28]) or paraspeckles [29].