hDOT1L retains CALM–AF10 in the nucleus. (a) Subcellular distribution of wild-type and OM–LZ deletion mutants, Flag–CALM–AF10 and CALM in U2OS cells. Transfected cells (red) are indicated with arrows. Nuclei are stained with DAPI (blue). (b) Analysis of nuclear staining by Flag antibody with confocal microscopy. (c) Immnofluorescent staining of U2OS cells cotransfected with hDOT1L (green) and Flag–CALM–AF10 (red). (d) Quantification of the cells presented in c. N, cells expressed in the nucleus; C, cells expressed in the cytoplasm. (e) Confocal microscopy analysis of the nuclear localization of hDOT1L and CALM–AF10 when coexpressed. The two staining patterns observed are shown. The pattern shown in the lower panels with more dots was predominant (~80%). The scale bar represents 10 μm in a, b and e, and 20 μm in c.