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Functional Assessment of Kinesin-7 CENP-E in Spermatocytes Using In Vivo Inhibition, Immunofluorescence and Flow Cytometry
Published on: December 28, 2021
Spermatogenesis does not require the local production of follistatin
S-Y Lin1, J R Morrison, M M Matzuk
1Monash Institute of Medical Research, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia.
Abstract:
It has been proposed that follistatin can modulate the actions of activins and/or other members of the transforming growth factor-beta superfamily of proteins on testicular function, since mice overexpressing follistatin showed spermatogenic disruption. However, since mice with targeted disruption of the follistatin gene die soon after birth, it is not feasible to determine the effect of the absence of follistatin on testicular function using this model. To further understand the role of follistatin on the development and maintenance of spermatogenesis, fetal testes, collected by Caesarean section at day 18 of gestation from follistatin null mice, were transplanted to the external ear of castrated recombination activating gene 1 immunocompromised male mice. The testicular grafts were then analysed 7-8 weeks after transplantation and showed that full spermatogenesis developed in both the testes of wild-type and follistatin null mice. This study indicates that, if follistatin is required to modulate spermatogenic development, it is not supplied by local testicular production but by circulating follistatin from the host mouse.
Insights
Follistatin does not appear essential for testicular development. If follistatin modulates spermatogenesis, it relies on circulating sources, not local testicular production, according to this study.
Area of Science:
- Reproductive biology
- Endocrinology
- Developmental biology
Background:
- Follistatin (FS) is hypothesized to regulate testicular function by modulating activins and other TGF-β superfamily members.
- Overexpression of follistatin in mice has been linked to disrupted spermatogenesis.
- Follistatin null mice die perinatally, preventing direct study of its absence on testicular function.
Purpose of the Study:
- To investigate the role of follistatin in the development and maintenance of spermatogenesis.
- To determine if local testicular production of follistatin is necessary for normal testicular function.
Main Methods:
- Fetal testes from follistatin null and wild-type mice were collected at day 18 of gestation.
- Testicular grafts were transplanted into the ears of castrated, immunocompromised mice (RAG1-/-).
- Grafts were analyzed after 7-8 weeks to assess spermatogenesis.
Main Results:
- Full spermatogenesis was observed in transplanted testes from both wild-type and follistatin null mice.
- This indicates that the absence of follistatin did not prevent the development of spermatogenesis in the grafted testes.
- The findings suggest that follistatin's role, if any, in spermatogenesis is not dependent on local testicular production.
Conclusions:
- Follistatin is not essential for the development of spermatogenesis in the studied model.
- Circulating follistatin from the host environment, rather than local testicular production, may be the source if follistatin modulates spermatogenic development.
- This study utilized a novel transplantation model to overcome limitations of existing follistatin knockout mouse models.
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