MFAP1 and PRPF38A nuclear foci appear after mitosis, before nuclear speckle reassembly. (A and B) Maximum-intensity projections of U2OS telophase daughter cells expressing GFP-MFAP1 (green) and immunostained with either anti-SC35 (A) or anti-SON (B) antibodies (red) to mark nuclear speckles. (C) Maximum-intensity projections of U2OS telophase daughter cells expressing GFP-PRPF38A (GFP-PR38A, green) and immunostained with anti-SON antibody (red). DNA (DAPI) is shown in blue (A–C). (D) Optical section showing U2OS telophase daughter cells expressing GFP-MFAP1 (green) and coimmunostained with antibodies for coilin (red) and SON (blue). Boxed areas are magnified (right panels). (E) Live-cell imaging (Video 5) of telophase U2OS cells coexpressing mCherry-SON (red) and GFP-MFAP1 (green) showing nuclear entry and formation of MFAP1 foci while SON is still present in cytoplasmic foci. Time (in minutes) after start of mitosis is shown in the top left corners. Boxed areas are magnified (top panels) in grayscale. Scale bars: main panels, 10 µm; insets, 2 µm.