ET analysis of MT organization in the centrosomal region of a migrating cerebellar granule neuron. (A) A selected tomographic slice showing MTs (arrowheads), the centrioles (C), and a portion of the nucleus (N). The black arrow indicates the direction of migration. (B) Corresponding 3D model showing the centrioles (blue cylinders), the MTs (green lines), and the nucleus (gray). (C) Model indicating distribution of MT minus ends (magenta spheres) and MT plus ends (turquoise spheres). Bar, 1 µm. (D–F) Quantification of the distribution of MT minus ends with respect to the centrosome as identified by ET of three different migratory neurons. See also Fig. S1.