NOD-mCherry–expressing cells do not form a well-defined metaphase plate. (A–D) Two-color confocal imaging of GFP–α-tubulin (green)– and NOD-mCherry (red)–expressing S2 cells. (A) Selected frames from a time lapse of a cell with a pair of sister chromatids that are attached to the same pole (arrow). The aberrant attachment state persists and anaphase onset (AO) ensues without error correction. See Video 1. (B and C) Chromosomes move away from the poles but fail to align along a well-defined metaphase plate, particularly in cells expressing high levels of NOD-mCherry. See Video 2. (D) Selected micrographs from a time lapse of a NOD-mCherry–expressing cell as it progresses through mitosis. A mixture of attachment states are established within the first 10 min of nuclear envelope breakdown and persist until the cell enters anaphase with uncorrected syntelic attachments, resulting in chromosome mis-segregation and multiple nuclei. See Video 3. Bars, 10 µm.