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Mouse Oocyte Microinjection, Maturation and Ploidy Assessment
Published on: July 23, 2011
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MICROINJECTION OF TOAD SPERM INTO OOCYTES UNDERGOING MATURATION DIVISION
1Zoological Institute, Faculty of Science, Hokkaido University, Sapporo, 060, Japan.
Development, Growth & Differentiation
|June 7, 2023
Summary
Sperm injected into mature frog eggs develop into pronuclei and synthesize DNA. Sperm injected into immature oocytes show varied responses depending on the stage, revealing cytoplasmic regulation of nuclear behavior.
Area of Science:
- Developmental Biology
- Cell Biology
- Reproductive Biology
Background:
- Sperm-nucleus transformation is crucial for fertilization.
- Oocyte maturation involves complex cytoplasmic changes.
- Understanding sperm-oocyte interactions is key to reproductive processes.
Purpose of the Study:
- To investigate sperm behavior within oocytes at different maturation stages.
- To elucidate the role of oocyte cytoplasm in regulating sperm nucleus transformation.
- To establish a method for studying cytoplasmic influences on nuclear events.
Main Methods:
- Detergent treatment of Bufo bufo japonicus spermatozoa to remove the plasma membrane.
- Microinjection of treated spermatozoa into oocytes at various meiotic stages.
- Observation of sperm nucleus behavior, chromosome formation, and DNA synthesis.
- Induction of maturation in oocytes using progesterone.
Main Results:
- Injected sperm transformed into pronuclei and synthesized DNA in mature oocytes.
- Sperm remained unchanged in oocytes with intact germinal vesicles (GV).
- Sperm exhibited stage-specific nuclear changes (chromosome formation, vesicular nuclei, condensed chromosomes) in synchrony with oocyte maturation, demonstrating cytoplasmic influence.
Conclusions:
- Oocyte cytoplasm regulates sperm nucleus behavior during maturation.
- Detergent-treated sperm injection is a viable method to study cytoplasmic control of nuclear events.
- The study provides insights into the molecular mechanisms governing sperm activation and nuclear reprogramming.
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