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Published on: February 6, 2018
MFN1 and MFN2 Are Dispensable for Sperm Development and Functions in Mice
Junru Miao1,2, Wei Chen2, Pengxiang Wang1
1Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241, China.
Abstract:
MFN1 (Mitofusin 1) and MFN2 (Mitofusin 2) are GTPases essential for mitochondrial fusion. Published studies revealed crucial roles of both Mitofusins during embryonic development. Despite the unique mitochondrial organization in sperm flagella, the biological requirement in sperm development and functions remain undefined. Here, using sperm-specific Cre drivers, we show that either Mfn1 or Mfn2 knockout in haploid germ cells does not affect male fertility. The Mfn1 and Mfn2 double knockout mice were further analyzed. We found no differences in testis morphology and weight between Mfn-deficient mice and their wild-type littermate controls. Spermatogenesis was normal in Mfn double knockout mice, in which properly developed TRA98+ germ cells, SYCP3+ spermatocytes, and TNP1+ spermatids/spermatozoa were detected in seminiferous tubules, indicating that sperm formation was not disrupted upon MFN deficiency. Collectively, our findings reveal that both MFN1 and MFN2 are dispensable for sperm development and functions in mice.
Insights
Mitofusin 1 (MFN1) and Mitofusin 2 (MFN2) are not essential for sperm development or function in mice. Knocking out these genes in sperm did not impact male fertility or sperm formation.
Area of Science:
- Cell Biology
- Reproductive Biology
- Mitochondrial Dynamics
Background:
- Mitofusins (MFN1 and MFN2) are critical GTPases for mitochondrial fusion, with established roles in embryonic development.
- The specific function of mitofusins in sperm development and function remains largely uncharacterized due to unique mitochondrial structures in flagella.
Purpose of the Study:
- To investigate the biological necessity of MFN1 and MFN2 in mouse sperm development and function.
- To determine if the absence of MFN1 and MFN2 impacts male fertility and spermatogenesis.
Main Methods:
- Utilized sperm-specific Cre drivers to generate MFN1 and MFN2 knockout mice.
- Analyzed testis morphology, weight, and spermatogenesis markers (TRA98, SYCP3, TNP1) in knockout and wild-type littermate controls.
Main Results:
- Single knockouts of MFN1 or MFN2 in haploid germ cells did not impair male fertility.
- Mice lacking both MFN1 and MFN2 showed normal testis morphology and weight.
- Spermatogenesis proceeded normally in double knockout mice, with all germ cell types detected.
Conclusions:
- MFN1 and MFN2 are dispensable for successful sperm development and function in mice.
- Mitochondrial fusion mediated by MFN1 and MFN2 is not required for male gamete formation or fertility.
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