Merotelic kinetochore attachment in oocyte meiosis II causes sister chromatids segregation errors in aged mice.

ABSTRACT: Mammalian oocyte chromosomes undergo 2 meiotic divisions to generate haploid gametes. The frequency of chromosome segregation errors during meiosis I increase with age. However, little attention has been paid to the question of how aging affects sister chromatid segregation during oocyte meiosis II. More importantly, how aneuploid metaphase II (MII) oocytes from aged mice evade the spindle assembly checkpoint (SAC) mechanism to complete later meiosis II to form aneuploid embryos remains unknown. Here, we report that MII oocytes from naturally aged mice exhibited substantial errors in chromosome arrangement and configuration compared with young MII oocytes. Interestingly, these errors in aged oocytes had no impact on anaphase II onset and completion as well as 2-cell formation after parthen

SUBMITTER: Cheng JM 

PROVIDER: S-EPMC5553406 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature