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Updated: Aug 11, 2026
12:40
High Throughput Microinjections of Sea Urchin Zygotes
Published on: January 21, 2014
Calcium-responsive contractility during fertilization in sea urchin eggs
Christianna Stack1, Amy J Lucero, Charles B Shuster
1Department of Biology, New Mexico State University, Las Cruces, NM 88003-8001, USA.
Summary
Sea urchin fertilization involves cortical F-actin changes. Myosin II responds to calcium signals and aids in remodeling the actomyosin cytoskeleton during early development.
Area of Science:
- Cell Biology
- Developmental Biology
- Marine Biology
Background:
- Fertilization triggers significant reorganization of the oocyte cytoskeleton.
- Sea urchin eggs exhibit a dramatic increase in cortical F-actin upon fertilization.
- The specific role of myosin II during fertilization is not well understood.
Purpose of the Study:
- To investigate the role and contractility of myosin II in sea urchin eggs during fertilization.
- To determine if myosin II responds to fertilization-associated calcium signals.
- To understand myosin II's contribution to cortical cytoskeleton remodeling post-fertilization.
Main Methods:
- Time-lapse microscopy of Lytechinus pictus eggs.
- Observation of cell surface dynamics following sperm binding.
- Induction of calcium-dependent contractility in unfertilized eggs.
- Inhibition of myosin II activity.
Main Results:
- A calcium-dependent cell surface deflection was observed after sperm binding.
- Intracellular calcium mobilization in unfertilized eggs induced a contractile response.
- Inhibition of myosin II delayed the absorption of the fertilization cone.
Conclusions:
- Myosin II is localized to the cortical cytoskeleton before and after fertilization.
- Myosin II contractility is dependent on calcium signaling, similar to egg activation.
- Myosin II plays a role in the remodeling of the cortical actomyosin cytoskeleton during the first zygotic cell cycle.
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