Multipolar spindles form by two mechanisms in LIC1 and 2 morphant embryos. Mitotic spindles were imaged live in Xenopus embryos using GFP–α-tubulin (green) and mCherry-H2B (magenta). (A) Bipolar spindles assembled and proceeded normally through mitosis and cytokinesis in controls (Ctrl). (B) An LIC morphant that formed a multipolar spindle at the onset of mitosis and subsequently failed cytokinesis (arrows). (C) An LIC morphant that assembled a bipolar spindle, which became multipolar when spindle poles fragmented (arrows). (D) Pole fragmentation was also seen in multipolar LIC MO spindles (arrows). Bars, 10 µm; time stamps display minutes and seconds.