deficiency in mouse oocytes during in vitro maturation increases chromosome segregation errors with a reduced BUBR1 at kinetochore.

Purpose: This study aimed to investigate the molecular mechanisms associated with chromosome segregation errors caused by intrinsic oxidative stress during in vitro oocyte maturation (IVM) using oocytes from -deficient (KO) mice.

Methods: Ovulated or in vitro matured cumulus-cells oocyte complexes (COCs) were collected from wild-type (WT) and KO mice and evaluated chromosome alignment, chromosome segregation, meiotic progression, and BUBR1 and REC8 protein expression levels.

Results: In 21% O IVM, the KO had significantly higher frequencies of chromosome misalignment and segregation errors compared to the WT, and they also reached Germinal Vesicle Break Down (GVBD) and M I stages peak earlier and showed a shorter M I stage residence time compared to the WT.