Nur1-Clb2 causes a mitotic exit defect.

<p>Nur1-Clb2 and Nur1-Clb2ΔCdk cells were synchronized in G1 by α-factor treatment and released to progress through the cell cycle at 36°C, before being rearrested in the following G1. At time points throughout the cell cycle we monitored, <b>A</b>. Cell cycle progression by FACS analysis of DNA content. <b>B</b>. Western blot analysis of the cell cycle markers securin, Clb2, Sic1 and Orc6, and <b>C</b>. The percentages of cells displaying metaphase (1–3 µm) or anaphase (>3 µm) spindles were scored. 100 cells were counted at each time point.