Aurora B kinase colocalizes with telomeres in metaphase and controls sister chromatid telomere dispersion and disjunction. (A) Movie of a cell expressing Taz1-rfp (telomeres, red), Ark1-gfp (Aurora, green), and Cdc11-cfp (SPB, blue) during mitotic progression. In metaphase (first four panels), Aurora transiently colocalizes to telomeres (arrows), whereas in anaphase (last two panels), it is absent from telomeres and present at the spindle midzone. (B) Schematic description of the procedure used to specifically inhibit Aurora kinase in early mitosis. (C) cdc25-22 ark1-as3 (red, n = 98, and black, n = 62) or cdc25-22 (gray, n = 60) cells were synchronized in G2 (36°C) and released in metaphase (25°C) before adding 10 µM Napp1 (Aurora inhibition). Synchronized mitotic cells were filmed through mitosis in the presence (Aurora inhibition, red) or absence (No inhibition or control, gray and black) of 10 µM Napp1 and the number of Taz1 dots was counted according to spindle length. The data shown are from a single representative experiment out of three repeats. (D) Example of the phenotypes seen in cdc25-22 ark1-as3 cells treated or not with 10 µM Napp1. Note that after Aurora inhibition, in a proportion of cells, centromeres are separated (Mis6 signal, left) but telomeres (Taz1 signal, left, or Pot1 signal, right) remain as clusters.