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Multi-Photon Laser Ablation of Cytoplasmic Microtubule Organizing Centers in Mouse Oocytes
Published on: November 11, 2022
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Two pathways regulate cortical granule translocation to prevent polyspermy in mouse oocytes
Liam P Cheeseman1, Jérôme Boulanger1, Lisa M Bond1
1Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK.
Nature Communications
|December 20, 2016
Summary
Cortical granules prevent polyspermy by blocking extra sperm. Two mechanisms, myosin Va and vesicle hitchhiking, drive their movement. Defects in this process may cause miscarriages.
Area of Science:
- Reproductive Biology
- Cell Biology
- Molecular Biology
Background:
- Fertilization requires a single sperm to fertilize an egg.
- Polyspermy, or fertilization by multiple sperm, is prevented by the zona pellucida becoming impermeable.
- Cortical granule exocytosis drives zona pellucida hardening, but the transport mechanism is unclear.
Purpose of the Study:
- To investigate the mechanisms of cortical granule translocation in live mammalian oocytes.
- To identify the molecular motors and pathways involved in cortical granule transport.
Main Methods:
- Utilized live imaging of mammalian oocytes with Rab27a as a marker for cortical granules.
- Investigated the roles of myosin Va and myosin Vb in cortical granule movement.
- Examined the interaction between cortical granules and Rab11a vesicles.
Main Results:
- Identified two distinct mechanisms for cortical granule transport: myosin Va-dependent movement along actin filaments.
- Discovered an "vesicle hitchhiking" mechanism where cortical granules associate with Rab11a vesicles powered by myosin Vb.
- Inhibition of cortical granule translocation significantly impaired the block to sperm entry.
Conclusions:
- Cortical granule translocation is a complex process involving multiple molecular motors and interactions.
- Defects in cortical granule transport may lead to polyspermy and contribute to early pregnancy loss.
- Further research into these mechanisms could offer insights into infertility and miscarriage causes.
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