Fig. 5. Historic and high-resolution views of the kinetochore-microtubule interface. (A) Original description of the `leitkörpen' (`the leading body') as the interface between chromosomes and the spindle in Salamander spermatocytes [adapted from the original (Metzner, 1894)]. (B) A single 16 nm thick slice from a 10-section tomographic volume reconstruction of the microtubule-kinetochore interface from PtK1 cells prepared by high-pressure freezing/freeze substitution. Note that forked microtubule plus ends are embedded in the kinetochore outer plate (arrows). (This picture was kindly provided by Bruce McEwen, Wadsworth Center, Albany, NY.) As a key to scale, the diameter of a microtubule is 25 nm.