Figure 2.

The effect of Nuf2 depletion on kMT binding. Electron micrographs of HeLa cells 48 h after mock-transfection (A-C) or transfection with hNuf2-siRNA (D-H). Arrows indicate typical examples of the robust (A-C) and deficient (D-H) bundles of microtubules associated with kinetochores of mock- and siRNA-transfected cells. (A) Low magnification view of a single serial section of a mock-transfected control cell. The well-formed metaphase plate persisted through all serial sections of the cell. (B and C) Serial section views of a kinetochore from a control cell. All kinetochores that were followed through serial sections had robust kinetochore fibers. (D) Low-magnification view of a single serial section from a transfected cell. Although some sections gave the appearance of partial metaphase alignment, this was not well maintained through the serial sections and virtually no kinetochore fibers were found. (E and F) Serial section views of a kinetochore from a transfected cell. It was more difficult to find kinetochores in transfected cells than in controls cells (see Table 1), and only a few of the kinetochores examined had more than 6-8 kMTs bound. (G and H) Serial section views from a transfected cell showing lateral interactions between spindle MTs and the centromere region of a chromosome. Scale bars: (A and D) 1 μm; (B, C, E, F, G, and H) 400 nm.