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Identification of Fas antigen associated with apoptotic cell death in murine ovary
Abstract:
The majority of ovarian follicles including oocytes undergo atresia through a mechanism involving apoptotic cell death. The mechanisms underlying atresia remain to be clarified. In the present study, we detected the expression of the Fas antigen (Fas), which is a cell-surface protein to modulate apoptosis, in murine ovarian oocytes and hyperovulated eggs as well as in several control tissues. Substantial decline in Fas mRNA was found in atretic follicles which were injected with pregnant mare's serum gonadotropin (PMSG) on day 3. The observed decreases in mRNA of Fas could not be attributed to a generalized degradation of cellular RNA during atresia, as evidenced by the presence of intact 18S and 28S ribosomal RNA as well as constitutive expression of EF-1 alpha mRNA in atretic follicles. The data obtained indicate that apoptotic cell death of oocytes seemed to be associated with internucleosomal DNA fragmentation regulated by Fas molecule expressed in atretic ovarian follicles.
Insights
Ovarian follicle atresia involves programmed cell death. This study found that the Fas molecule
Area of Science:
- Reproductive Biology
- Cell Biology
- Molecular Biology
Background:
- Ovarian follicle atresia, a major cause of oocyte loss, involves programmed cell death.
- The precise molecular mechanisms driving atresia remain incompletely understood.
- The Fas antigen, a key regulator of apoptosis, is implicated in cellular death pathways.
Purpose of the Study:
- To investigate the role of the Fas antigen in the process of ovarian follicle atresia.
- To examine Fas expression in murine oocytes and eggs during follicular development and atresia.
- To clarify the molecular mechanisms underlying oocyte apoptosis during atresia.
Main Methods:
- Detection of Fas antigen expression in murine ovarian oocytes and eggs.
- Quantitative analysis of Fas mRNA levels in atretic and healthy ovarian follicles.
- Assessment of RNA integrity (18S, 28S rRNA) and constitutive mRNA expression (EF-1 alpha) in atretic follicles.
Main Results:
- Significant downregulation of Fas mRNA was observed in atretic ovarian follicles after pregnant mare's serum gonadotropin (PMSG) administration.
- Decreased Fas mRNA levels were not due to general RNA degradation, as ribosomal RNA and EF-1 alpha mRNA remained intact.
- Oocyte apoptotic cell death correlated with internucleosomal DNA fragmentation, suggesting Fas regulation.
Conclusions:
- The Fas molecule plays a role in regulating apoptotic cell death of oocytes during ovarian follicle atresia.
- Downregulation of Fas mRNA is associated with oocyte apoptosis and DNA fragmentation in atretic follicles.
- Further research into Fas-mediated pathways is crucial for understanding ovarian follicle dynamics.