Fig. 8. Electron microscopy of the perinuclear cage in a HeLa cell expressing TPPP/p25. (A) Low power view of the perinuclear cage. (B) Enlarged view of the area framed in A showing that the cage consists of microtubules (arrows) organized into roughly parallel bundles running at different angles in close proximity to the nuclear membrane. N, nucleus. Bar, 300 nm (A); 150 nm (B).