Using FRET to Define Cdk1-Dependent Ordering of Events During Exit from Second Meiotic M-Phase in Oocytes

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Exit from M-phase is critical for cell viability, with errors leading to aneuploidy, cancer, and pregnancy failure.
• Oocyte meiosis II (MII) exit is a unique, sperm-triggered event involving pronuclear formation, but coordination mechanisms are poorly understood.
• Cyclin-dependent kinase 1 (Cdk1) inactivation drives M-phase exit, yet its precise role in MII exit remains unclear due to experimental difficulties.

Purpose of the Study:

• To develop and present a protocol for detailed analysis of Cdk1 activity during fertilization in live mouse oocytes.
• To investigate the coordination of molecular events during MII exit using advanced imaging techniques.

Main Methods:

• Utilized a Cdk1 Fluorescence Resonance Energy Transfer (FRET) biosensor for real-time monitoring of Cdk1 activity.
• Employed time-lapse imaging to capture dynamic changes during fertilization and MII exit.
• Developed a protocol for in-depth analysis of Cdk1 activity in live mouse oocytes.

Main Results:

• Successfully detailed a protocol for analyzing Cdk1 activity throughout fertilization in live mouse oocytes.
• Demonstrated the utility of FRET biosensors and time-lapse imaging for studying challenging cell-cycle events.
• Provided new insights into the orchestration of MII exit by Cdk1.

Conclusions:

• The developed protocol enables robust interrogation of Cdk1 activity during fertilization.
• Time-lapse FRET imaging is a powerful tool for dissecting complex cell-cycle regulation.
• Further understanding of MII exit mechanisms can inform reproductive health and cancer research.