Improved ultrastructure of the desmosome-intermediate filament complex in MCF-7 breast cancer cells

We report on the application of variations to the traditional TEM processin g methods, which provide improved clarity of the desmosome-cytoskeleton com plex of MCF-7 human breast cancer cells. A more comprehensive understanding of the ultrastructure is presented, which in the past has been demonstrate d in diagrammatic form based on numerous electron micrographs. Ultrastructu ral analysis shows that intermediate filament bundles do not terminate at t he desmosome structure, but instead are continuous into the cytoplasm. Furt hermore only a minor proportion of individual filaments are in actual conta ct with the desmosome plaque. Intermediate filaments were also observed thr oughout the cytoplasm and to the surface of the nuclear membrane. Extractio n protocols allowed clear identification of other cellular features such as nuclear pores, which are approximately 80-85 nm in diameter, and were best viewed in sections cut tangentially to the nuclear surface.