Zw10 is a spindle assembly checkpoint protein that regulates meiotic maturation in mouse oocytes.

Faithful chromosome segregation during the cell cycle is ensured by the spindle assembly checkpoint (SAC). Although SAC activity is highly conserved and most organisms share common SAC components, additional proteins that regulate SAC activity to ensure high fidelity chromosome segregation are present in higher eukaryotes. Zw10 is one of these additional SAC components. Although Zw10 has been demonstrated to be involved in SAC activity during mitosis, little is known about its role during oocyte meiosis. Here, we report that Zw10 is localized at the kinetochore and is required for SAC activation during meiotic maturation. Knockdown of Zw10 led to precocious polar body extrusion by impairing Mad2 recruitment at kinetochores. Moreover, Zw10 knockdown impaired chromosome alignment and kinetochore-microtubule attachment, increasing the incidence of aneuploidy. Furthermore, Zw10 expression decreased with maternal age, suggesting that Zw10 is associated with the age-related increase in the incidence of aneuploidy. Together, our results demonstrate that Zw10 is localized at kinetochores and functions as an essential SAC component in mouse oocytes.