Fig. 9. Immunolocalization of XCAP-E and topoII on the nucleolus in control cells and after actinomycin treatment. XL2 cells were incubated for 6 hours in the medium with 5 µg/ml actinomycin D (E-H) or without the drug (A-D). After fixation, cells were processed for immunofluorescence staining with polyclonal anti-XCAP-E1 (C,G) and monoclonal anti-topoII (D,H) antibodies. Cells were observed by phase contrast microscopy (A,E) and stained for DNA visualization with DAPI (B,F). Bar, 5 µm.