The length of the outer plate and the distance of the interkinetochore in CENP-S–deficient cells. (A) Electron micrograph showing a typical image of the kinetochore outer plate in wild-type (1 and 1′) or CENP-S–deficient cells (2 and 2′). (B) Numbers of identifiable outer plates per cell (mean ± SD). Approximately 35 serial sections were made for each cell, and the numbers of outer plates were counted. (C) Distribution of the outer plate length in wild-type or CENP-S–deficient cells. In both cell lines, two peaks with distribution were observed. The two peaks in the distribution of the plate length are likely caused by differences in sample orientation. As the orientation of some cells is not plane of the section, the length of plates varies depending on the angle of the section against a chromosome. (D) Distance between outer plate and electron-dense chromatin region in wild-type or CENP-S–deficient cells. (E) Distances between Ndc80 and Ndc80 or CENP-T and CENP-T of control or CENP-S– or CENP-X–deficient metaphase cells in the absence of microtubules. Arrows indicate sister kinetochore pairs. (D and E) Error bars represent SD. Bars: (A) 200 nm; (E) 5 µm.