Cdk1 negatively regulates the spindle localization of Prc1 in mouse oocytes.

Chromosome segregation requires the formation of a bipolar spindle. The timely bipolarization of the acentrosomal spindle during meiosis I in mouse oocytes depends on the antiparallel microtubule crosslinker Prc1. How Prc1 is regulated in oocytes remains poorly understood.

Prc1-rich kinetochores are required for error-free acentrosomal spindle bipolarization during meiosis I in mouse oocytes.

Acentrosomal meiosis in oocytes represents a gametogenic challenge, requiring spindle bipolarization without predefined bipolar cues. While much is known about the structures that promote acentrosomal microtubule nucleation, less is known about the structures that mediate spindle bipolarization in mammalian oocytes. Here, we show that in mouse oocytes, kinetochores are required for spindle bipolarization in meiosis I.