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Updated: Mar 23, 2026
Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes
Published on: September 13, 2022
Quality control in oocytes by p63 is based on a spring-loaded activation mechanism on the molecular and cellular
Daniel Coutandin1,2,3, Christian Osterburg1,2,3, Ratnesh Kumar Srivastav1,2,3
1Institute of Biophysical Chemistry, Goethe University, Frankfurt, Germany.
Abstract:
Mammalian oocytes are arrested in the dictyate stage of meiotic prophase I for long periods of time, during which the high concentration of the p53 family member TAp63α sensitizes them to DNA damage-induced apoptosis. TAp63α is kept in an inactive and exclusively dimeric state but undergoes rapid phosphorylation-induced tetramerization and concomitant activation upon detection of DNA damage. Here we show that the TAp63α dimer is a kinetically trapped state. Activation follows a spring-loaded mechanism not requiring further translation of other cellular factors in oocytes and is associated with unfolding of the inhibitory structure that blocks the tetramerization interface. Using a combination of biophysical methods as well as cell and ovary culture experiments we explain how TAp63α is kept inactive in the absence of DNA damage but causes rapid oocyte elimination in response to a few DNA double strand breaks thereby acting as the key quality control factor in maternal reproduction.
Insights
Mammalian oocytes utilize TAp63α, a p53 family member, to eliminate damaged eggs. This protein remains inactive until DNA damage triggers its rapid activation, ensuring maternal reproductive quality.
Area of Science:
- Reproductive biology
- Molecular cell biology
- Genetics
Background:
- Mammalian oocytes arrest in meiosis I, with high TAp63α levels sensitizing them to DNA damage.
- TAp63α exists as an inactive dimer, requiring activation upon DNA damage detection.
Purpose of the Study:
- To elucidate the mechanism of TAp63α activation in oocytes.
- To understand TAp63α's role as a quality control factor in maternal reproduction.
Main Methods:
- Biophysical methods
- Cell culture experiments
- Ovary culture experiments
Main Results:
- TAp63α dimer is a kinetically trapped state.
- Activation involves a spring-loaded mechanism, not requiring new protein synthesis.
- Activation is linked to the unfolding of an inhibitory structure blocking tetramerization.
Conclusions:
- TAp63α is maintained in an inactive state without DNA damage.
- It rapidly eliminates oocytes with even minimal DNA double-strand breaks.
- TAp63α functions as a critical quality control factor in maternal reproduction.
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