Submitted to: Journal of Molecular Reproduction and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 25, 1996
Publication Date: N/A
Interpretive Summary: Primordial germ cells (PGCs) are the early embryonic cells that eventually give rise to egg or sperm in the fully developed animal. Mouse PGCs can be cultured as continuous cell lines and as such can be used as embryonic stem cells, i.e., cells capable of repopulating the early embryo & contributing to all of its tissues during development. The present study identifies monoclonal antibodies and lectins (sugar binding proteins) that PGCs were detected at different stages in the development of the genital ridge in 18- 26 day pig embryos. The markers also served to identify the cells as they were harvested and cultured from the 26-day pig genital ridge, and confirmed alkaline phosphatase activity as an additional marker of pig PGCs. The study provides basic information as to the number and location of PGCs in the early pig embryo. The results also provide the means to study culture conditions for the propagation of the pig PGCs, because the pig PGCs can now be unequivocally identified in culture.
Technical Abstract: Monoclonal antibodies anti-SSEA-1 and EMA-1, and the lectins DBA and LTA, bound to the surface of large, round cells randomly distributed in the 26-day pig genital ridge. Other antibodies, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81, did not react with any cells in the pig genital ridge. SSEA-1-positive cells displayed pseudopods and appeared to migrate from th dorsal mesentery of the hindgut (18-day) to the primordium of the gonad (day 23) and entered the genital ridge by 26 days. The number of SSEA-1-positive cells associated with the dorsal mesentery and genital ridge markedly increased from the 18-day to the 26-day pig embryo. It was concluded that the SSEA-1-positive cells were primordial germ cells (PGCs). Using these markers and alkaline phosphatase histochemistry, pig PGCs derived from the 26-day genital ridge showed no proliferation when grown in STO co-culture in the presence of human LIF, bFGF and SCF.