Fig. 3. Nucleolar localization of pEg7 and topoII in the interphase nucleus. XL-2 cells were grown and fixed as described under Materials and Methods. Cell were then processed for double immunofluorescence staining (panels A-E) with an anti-pEg7G affinity-purified polyclonal antibody (C) and an anti-human topoII monoclonal antibody (D). The merged picture is shown in e. Cells were observed by phase contrast microscopy (A) and stained with DAPI (B). For electron microscopy (F-H) cell were fixed as described under Materials and Methods and then labeled for double immunogold electron microscopy with anti-pEg7G affinity-purified polyclonal antibody and anti-human topoII monoclonal antibody. Anti-Eg7 and anti-topoII antibodies were revealed with a secondary anti-rabbit antibody conjugated to a 5 nm gold particle (for pEg7) and an anti-mouse antibody conjugated to 10 nm gold particle (for topoII, arrows), respectively. Bar, 5 µm (A-E), 1 µm (F) and 0.2 µm (G,H).