Related Experiment Video
Updated: Apr 3, 2026
Oct4GiP Reporter Assay to Study Genes that Regulate Mouse Embryonic Stem Cell Maintenance and Self-renewal
Published on: May 30, 2012
Oct4-GFP expression during transformation of gonocytes into spermatogonial stem cells in the perinatal mouse testis
Ruili Li1, Amanda Vannitamby2, Jian-Guo Zhang3
1FD Stephens Surgical Research Group, Murdoch Childrens Research Institute, Parkville, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Parkville, VIC 3052, Australia.
Background/Aim:
In cryptorchidism perinatal failure to switch off Oct4, a germ cell (GC) marker, may lead to carcinoma in situ. We aimed to analyze Oct4 expression during mouse gonocyte transformation into spermatogonial stem cells (SSC).
Materials And Methods:
Testes from OG2 (Oct4-promoter driven eGFP) mice at embryonic day (E) 17 and postnatal day P0-10 underwent immunohistochemistry and immunoblotting. Antibodies against MVH, AMH, Ki67, and c-Kit were visualized by confocal microscopy. Numbers of Oct4-GFP(+) GC and Oct4-GFP(-) GC/tubule were counted using ImageJ. Data were analyzed using nonparametric one-way ANOVA.
Results:
GC from E17-P4 were Oct4-GFP(+). Numbers of Oct4-GFP(-) GC/tubule increased from P6-10, whereas Oct4-GFP(+) GC/tubule numbers remained similar between P6 and P10. Sertoli cells proliferated from E17-P10, whereas GC only proliferated from P2. Gonocytes (Oct4-GFP(+)/c-Kit(-)) central in tubules migrated to the basement membrane to become prospermatogonia (Oct4-GFP(+)/c-Kit(-)) and then SSC (Oct4-GFP(+)/c-Kit(+)) from day 4 and further developed into Oct4-GFP(-)/c-Kit(+) at P6.
Conclusion:
In Oct4-GFP mice both centrally located gonocytes and prospermatogonia located at the tubular basement membrane were Oct4-GFP(+)/c-Kit(-) before further developing into SSC (Oct4-GFP(+)/c-Kit(+)). This indicates that Oct4 is important in gonocyte transformation into SSC. Understanding this process will aid GC tumor diagnostics and fertility potential in boys with UDT undergoing orchidopexy.
Insights
Oct4 expression is crucial for germ cell (GC) transformation into spermatogonial stem cells (SSC). This study tracks Oct4-GFP in mice, revealing its role in GC development and potential implications for cryptorchidism diagnostics.
Area of Science:
- Reproductive Biology
- Developmental Biology
- Stem Cell Biology
Background:
- Perinatal failure to downregulate Oct4, a germ cell marker, is linked to carcinoma in situ in cryptorchidism.
- Understanding germ cell transformation is vital for diagnosing and treating undescended testes (UDT).
Purpose of the Study:
- To analyze Oct4 expression during the transformation of mouse gonocytes into spermatogonial stem cells (SSCs).
Main Methods:
- Utilized Oct4-promoter driven eGFP (OG2) mice from embryonic day 17 to postnatal day 10.
- Performed immunohistochemistry and immunoblotting with antibodies for MVH, AMH, Ki67, and c-Kit.
- Quantified Oct4-GFP positive and negative germ cells (GCs) per tubule using ImageJ and analyzed data via nonparametric one-way ANOVA.
Main Results:
- Germ cells (GCs) were Oct4-GFP positive from embryonic day 17 to postnatal day 4.
- The number of Oct4-GFP negative GCs increased from postnatal day 6 to 10, while Oct4-GFP positive GCs remained constant.
- Gonocytes transitioned through prospermatogonia to SSCs, marked by changes in Oct4-GFP and c-Kit expression.
Conclusions:
- Oct4 is essential for the transformation of gonocytes into spermatogonial stem cells (SSCs).
- Both centrally located gonocytes and prospermatogonia express Oct4-GFP and are c-Kit negative before becoming SSCs.
- Insights into this process can improve diagnostic accuracy for germ cell tumors and assess fertility potential in boys with UDT undergoing orchidopexy.
