Related Experiment Video For BUBR1
Updated: May 31, 2025
Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes
Published on: September 13, 2022
Sod1 deficiency in mouse oocytes during in vitro maturation increases chromosome segregation errors with a reduced
Mitsuru Nago1,2, Masumi Yanai1, Mika Ishii1
1Laboratory of Animal Reproduction, Graduate School of Agricultural Sciences Yamagata University Tsuruoka Japan.
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 Sod1-deficient (Sod1KO) mice.
Methods:
Ovulated or in vitro matured cumulus-cells oocyte complexes (COCs) were collected from wild-type (WT) and Sod1KO mice and evaluated chromosome alignment, chromosome segregation, meiotic progression, and BUBR1 and REC8 protein expression levels.
Results:
In 21% O2 IVM, the Sod1KO 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. These changes were associated with a decrease in the recruitment of BUBR1 to kinetochores at M I stage, but there were no differences in the expression of REC8 between the two genotypes. Furthermore, the addition of L-ascorbic acid (AsA) or N-acetyl-L-cysteine (NAC) during IVM reduced the frequency of chromosome segregation errors in Sod1KO oocytes.
Conclusions:
Oxidative stress caused by Sod1 deficiency during IVM impairs the spindle assembly checkpoint function due to a decrease in the recruitment of BUBR1 to M I stage kinetochores, leading to abnormalities in meiotic progression and chromosome segregation.
Related Concept Videos
02:02Meiosis II
The timing and cell division patterns of meiosis differ between males and females. In male meiosis, the centrosomes are part of the formation of the meiotic spindle. However, in oocytes, including that of humans, Drosophila,...
01:21Nondisjunction
02:57Meiosis vs. Mitosis
Before the start of mitosis and meiosis I, the cell synthesizes DNA, resulting in two homologous copies of each chromosome. DNA synthesis is...
03:09Meiosis I
Prophase I is the most extended and complex step of meiosis I characterized by synapsis, chromosome pairing, and recombination of the homologous chromosomes. This process is facilitated by a proteinaceous structure called the...
02:07Oogenesis
02:19The Spindle Assembly Checkpoint
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...