Aurora B kinase erases monopolar microtubule-kinetochore arrays at the meiosis I-II transition

During meiosis, faithful chromosome segregation requires monopolar spindle microtubule-kinetochore arrays in MI to segregate homologous chromosomes, but bipolar in MII to segregate sister chromatids. Using fission yeasts, we found that the universal Aurora B kinase localizes to kinetochores in metaphase I and in the mid-spindle during anaphase I, as in mitosis; but in the absence of an intervening S phase, the importin a Imp1 propitiates its release from the spindle midzone to re-localize at kinetochores during meiotic interkinesis. We show that error-correctionactivity of kinetochore re-localized Aurora B becomes essential to erase monopolar arrangements from anaphase I, a prerequisite to satisfy the spindle assembly checkpoint (SAC) and to generate proper bipolar arrays at the onset of MII. This microtubule-kinetochore resetting activity of Aurora B at the MI-MII transition is required to prevent chromosome mis-segregation in meiosis II, a type of error often associated with birth defects and infertility in humans.

Automated summary

During meiosis, the localization and activity of Aurora B kinase are crucial for ensuring proper chromosome segregation. Research has shown that the relocalization activity of Aurora B kinase during meiotic interkinesis plays a key role in erasing monopolar arrangements, satisfying the spindle assembly checkpoint, and generating proper bipolar arrays.