Getting nuclei moving

Addition of a single fission yeast protein can induce nuclear oscillations in mitotic cells, even though these movements are normally seen only in meiotic cells, according to Kayoko Tanaka, Masayuki Yamamoto, and colleagues (University of Tokyo, Japan).

Fission yeast meiosis includes a thrashing about of the nucleus (also called horsetail nuclear movement [HNM]) that helps align homologous chromosomes. This oscillation is driven by a dynein–dynactin system. Cortex-localized dynein may be switched on at first one end of the cell and then the other. The dynein tugs on an astral array of microtubules called the horsetail astral array (HAA).

Mitotic cells lack both the HAA and any significant amounts of dynein and dynein-anchoring proteins. So it was a surprise when the Japanese group succeeded in inducing the mitotic appearance...