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Updated: Jun 26, 2026
Ovarian Tissue Culture to Visualize Phenomena in Mouse Ovary
Published on: June 19, 2018
Expression of ovarian tumour suppressor OPCML in the female CD-1 mouse reproductive tract
Jean S Fleming1, H James McQuillan, Melanie J Millier
1Department of Anatomy and Structural Biology, University of Otago School of Medical Sciences, Dunedin 9054, New Zealand. jean.fleming@otago.ac.nz
Abstract:
Opioid binding protein/cell adhesion molecule-like gene (OPCML) is frequently inactivated in epithelial ovarian cancer, but the role of this membrane protein in normal reproductive function is unclear. The ovarian surface epithelium (OSE) is thought to be the cell of origin of most epithelial ovarian cancers, some of which arise after transformation of OSE cells lining ovarian inclusion cysts, formed during ovulation. We used immunohistochemistry, immunoblotting and quantitative RT-PCR (qRT-PCR) to investigate OPCML expression in the uteri and ovaries of cycling 3-month CD-1 mice, as well as in ovaries from older mice containing inclusion cysts derived from rete ovarii tubules. Immunoblotting showed OPCML bands in uterine, but not whole ovarian or muscle extracts. Strong OPCML immunoreactivity was observed in oviduct, rete ovarii and uterus, whereas in ovary more immunoreactivity was seen in granulosa cells than OSE. No staining was observed in OSE around ovulation sites, where OSE cells divide to cover the site. OPCML immunoreactivity was also weaker in more dysplastic cells lining large ovarian inclusion cysts, compared with normal rete ovarii. No significant changes in Opcml mRNA expression were observed in whole ovarian and uterine extracts at different stages of the cycle. We conclude that murine OPCML is more consistently expressed in cells lining the uterus, oviduct and rete ovarii than in ovary and is not expressed in OSE associated with ovulation sites. This observation supports the hypothesis that a proportion of epithelial ovarian cancers arise from ductal cells and other epithelia of the secondary Mullerian system, rather than the OSE.
Insights
The opioid binding protein/cell adhesion molecule-like gene (OPCML) is expressed in the mouse oviduct, rete ovarii, and uterus, but not the ovarian surface epithelium (OSE) during ovulation. This suggests ovarian cancers may originate from other epithelia, not OSE.
Area of Science:
- Reproductive biology
- Molecular oncology
- Cell adhesion molecules
Background:
- Opioid binding protein/cell adhesion molecule-like gene (OPCML) is often inactivated in epithelial ovarian cancer.
- The function of OPCML in normal reproductive organs is not well understood.
- The ovarian surface epithelium (OSE) is a suspected origin for many ovarian cancers, potentially arising from inclusion cysts.
Purpose of the Study:
- To investigate the expression and role of OPCML in the female reproductive tract.
- To determine if OPCML is expressed in the OSE, particularly around ovulation sites.
- To explore the origin of epithelial ovarian cancers in relation to OPCML expression.
Main Methods:
- Immunohistochemistry, immunoblotting, and quantitative RT-PCR (qRT-PCR) were used.
- OPCML expression was examined in cycling and older CD-1 mice ovaries and uteri.
- Analysis included normal OSE, oviduct, rete ovarii, uterus, granulosa cells, and inclusion cysts.
Main Results:
- OPCML protein was detected in the mouse oviduct, rete ovarii, and uterus, but not whole ovarian or muscle extracts.
- Immunoreactivity was stronger in granulosa cells than OSE within the ovary.
- OPCML expression was absent in OSE at ovulation sites and reduced in dysplastic cells of inclusion cysts.
Conclusions:
- Murine OPCML is consistently expressed in the uterus, oviduct, and rete ovarii, but not significantly in the ovary or OSE.
- The lack of OPCML expression in OSE at ovulation sites supports the hypothesis that some ovarian cancers originate from secondary Mullerian system epithelia, not OSE.
