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Updated: Dec 9, 2025
Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes
Published on: September 13, 2022
CHK1 monitors spindle assembly checkpoint and DNA damage repair during the first cleavage of mouse early embryos
Jia-Qian Ju1, Xiao-Han Li1, Meng-Hao Pan1
1College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China.
Objectives:
DNA damage and errors of accurate chromosome segregation lead to aneuploidy and foetal defects. DNA repair and the spindle assembly checkpoint (SAC) are the mechanisms developed to protect from these defects. Checkpoint kinase 1 (CHK1) is reported to be an important DNA damage response protein in multiple models, but its functions remain unclear in early mouse embryos.
Materials And Methods:
Immunofluorescence staining, immunoblotting and real-time reverse transcription polymerase chain reaction were used to perform the analyses. Reactive oxygen species levels and Annexin-V were also detected.
Results:
Loss of CHK1 activity accelerated progress of the cell cycle at the first cleavage; however, it disturbed the development of early embryos to the morula/blastocyst stages. Further analysis indicated that CHK1 participated in spindle assembly and chromosome alignment, possibly due to its regulation of kinetochore-microtubule attachment and recruitment of BubR1 and p-Aurora B to the kinetochores, indicating its role in SAC activity. Loss of CHK1 activity led to embryonic DNA damage and oxidative stress, which further induced early apoptosis and autophagy, indicating that CHK1 is responsible for interphase DNA damage repair.
Conclusions:
Our results indicate that CHK1 is a key regulator of the SAC and DNA damage repair during early embryonic development in mice.
Insights
Checkpoint kinase 1 (CHK1) is crucial for early mouse embryo development, regulating the spindle assembly checkpoint (SAC) and DNA repair. Its loss causes cell cycle issues, DNA damage, and developmental failure.
Area of Science:
- Developmental Biology
- Cell Biology
- Genetics
Background:
- DNA damage and chromosome segregation errors cause aneuploidy and developmental defects.
- DNA repair and the spindle assembly checkpoint (SAC) are critical protective mechanisms.
- Checkpoint kinase 1 (CHK1) is implicated in DNA damage response, but its role in early mouse embryos is unclear.
Purpose of the Study:
- To investigate the function of CHK1 in early mouse embryonic development.
- To determine CHK1's role in DNA damage repair and the spindle assembly checkpoint (SAC).
Main Methods:
- Immunofluorescence staining, immunoblotting, and RT-PCR were employed.
- Analysis included reactive oxygen species (ROS) levels and Annexin-V staining.
- Cell cycle progression and embryonic development were monitored.
Main Results:
- Loss of CHK1 activity accelerated the first cell cycle but impaired development to morula/blastocyst stages.
- CHK1 regulates spindle assembly, chromosome alignment, and SAC activity via kinetochore-microtubule attachments and protein recruitment (BubR1, p-Aurora B).
- CHK1 deficiency resulted in embryonic DNA damage, oxidative stress, apoptosis, and autophagy.
Conclusions:
- CHK1 is essential for SAC function and DNA damage repair during early mouse embryonic development.
- CHK1 acts as a key regulator safeguarding genomic integrity and proper development.
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