FIG. 5.

Subcellular localization of PE38 mutants. SF-21 cells were transiently transfected with plasmids expressing FLAG-tagged PE38 or FLAG-tagged PE38 mutants. Epitope-tagged versions of IE1 and CAT served as controls for nuclear and cytoplasmic localization, respectively. After 18 h, gene expression was induced by heat shock. At 3 h after heat shock, cells were fixed in methanol and analyzed by indirect immunofluorescence. FLAG-PE38 and FLAG-tagged PE38 mutants were visualized with mouse M2 anti-FLAG monoclonal antibody and lissamine rhodamine-conjugated goat anti-mouse IgG-IgM antibodies (panels 1, 3, 5, 7, 9, and 11). Mouse anti-HA.11 monoclonal antibody was used to localize hemagglutinin epitope-tagged IE1 and CAT followed by incubation with lissamine rhodamine-conjugated anti-mouse IgG-IgM antibody (panels 13 and 15). Nuclei were visualized by staining with DAPI (panels 2, 4, 6, 8, 10, 12, 14, and 16). Micrographs of immunofluorescence and DAPI staining were taken from the same fields of cells.