Fig. 4.

Ultrastructure of Drosophila S2 cells undergoing mitosis. (A–C) metaphase; B and C are the enlarged insets indicated in A, showing the ultrastructure of kinetochores (arrowheads) and attached MTs. (D) Fine structure of a kinetochore fiber from a prometaphase. (E) Transverse section of the spindle from a cell in prometaphase. (F) High magnification of MTs from the inset in E; note the proteinaceous bridges (arrowheads) between MTs. (G) Ultrastructure of mother and daughter centrioles. Scale bar: 5 μm (A), 0.5 μm (B–E), 0.1 μm (F, G).