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Mouse oocytes injected with testicular spermatozoa or round spermatids can develop into normal offspring
1Department of Anatomy and Reproductive Biology, University of Hawaii School of Medicine, Honolulu 96822, USA.
Development (Cambridge, England)
|August 1, 1995
Summary
Genomic imprinting in male mice is completed before spermiogenesis begins. This study injected sperm and spermatid nuclei into oocytes, finding that sperm nuclei led to normal offspring, suggesting imprinting completion.
Area of Science:
- Reproductive Biology
- Developmental Biology
- Genetics
Background:
- Genomic imprinting is crucial for mammalian development.
- The precise timing of imprinting completion in male gametes remains unclear.
Purpose of the Study:
- To determine when genomic imprinting is completed during male gametogenesis in mice.
- To assess the developmental potential of oocytes injected with nuclei from different stages of male germ cells.
Main Methods:
- Nuclei from testicular spermatozoa and round spermatids were injected into mature mouse oocytes.
- Oocyte activation methods were varied for spermatid injections.
- Embryos were transferred to foster mothers to assess development to term.
Main Results:
- Oocytes injected with testicular spermatozoa resulted in 54.5% normal offspring.
- Oocytes injected with round spermatids (after artificial activation) resulted in 28.2% normal offspring.
- These findings suggest imprinting is complete before spermiogenesis.
Conclusions:
- Gametic imprinting in mouse male germ cells is completed before spermiogenesis.
- Testicular spermatozoa nuclei are more efficient than round spermatid nuclei for producing viable offspring in this experimental setup.