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Updated: Aug 7, 2026
07:45
Imaging Calcium in Drosophila at Egg Activation
Published on: August 6, 2016
Calcium signals for egg activation in mammals
Shunichi Miyazaki1, Masahiko Ito
1Department of Physiology, Tokyo Women's Medical University School of Medicine, Japan. shunm@research.twmu.ac.jp
Journal of Pharmacological Sciences
|June 27, 2006
Summary
Fertilization triggers calcium (Ca2+) release in eggs, initiating cell division. Sperm phospholipase C zeta (PLCzeta) is identified as the key factor inducing these crucial calcium oscillations.
Area of Science:
- Reproductive Biology
- Cellular Signaling
- Biochemistry
Background:
- Fertilization triggers a rise in intracellular calcium (Ca2+) concentration ([Ca2+]i), essential for egg activation across species.
- In mammals, this involves repetitive [Ca2+]i rises (oscillations) mediated by inositol 1,4,5-trisphosphate (IP3) receptors on the endoplasmic reticulum.
Purpose of the Study:
- To investigate the role of sperm phospholipase C zeta (PLCzeta) as the sperm factor inducing calcium oscillations during fertilization.
- To characterize the properties of PLCzeta related to its calcium oscillation-inducing activity.
Main Methods:
- Injection of PLCzeta-encoding RNA or recombinant PLCzeta into mouse eggs.
- In vitro enzymatic activity assays measuring Ca2+ sensitivity.
- Analysis of nuclear translocation ability of PLCzeta.
Main Results:
- PLCzeta demonstrated potent Ca2+ oscillation-inducing activity in mouse eggs.
- In vitro studies revealed PLCzeta's high sensitivity to Ca2+.
- PLCzeta exhibits nuclear translocation, suggesting a role in cell-cycle regulation of Ca2+ oscillations.
Conclusions:
- Sperm PLCzeta is a strong candidate for the sperm factor responsible for triggering fertilization-induced Ca2+ oscillations.
- PLCzeta's activity is critical for egg activation, including the resumption of meiosis and pronuclei formation.
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