Submitted to: Poultry and Avian Biology Reviews
Publication Type: Proceedings
Publication Acceptance Date: 9/10/2005
Publication Date: 10/12/2005
Citation: Bakst, M.R., Durand, P., Trefil, P., Brillard, J.P. 2005. Spermatogonial stem cells: What are they and why we should be interested. Proceeding: Incubation and Fertility Research Group, University of Lincoln, UK, September 2005. Poultry and Avian Biology Reviews. 16:181. Interpretive Summary:
Technical Abstract: We are involved in a cooperative research project that will expand our knowledge of the biology of spermatogonia, the testicular stem cell. We also aim to use this stem cell as a target cell for the production of transgenic poultry. To accomplish this goal, techniques for the isolation and partial purification of spermatogonia are being developed. This enriched population of spermatogonia will be cultured and allowed to propagate. The spermatogonia grown in culture will then be transfected with gene(s) possessing trait(s) having economic importance, and then transferred to recipient sterilized males. The recipient will be grown to maturity, semen collected, inseminated into hens, and fertility and genotype of progeny checked to determine whether the germ-cell transfer and transfection were successful. Continued spermatogenesis through adult life is contingent upon the spermatogonial stem cell. These diploid cells proliferate with some daughter cells entering meiosis while others remain as testicular stem cells. Unlike mammals, there is little fundamental information about spermatogonia in birds and little work has been done on germ cell transfer between individual birds. The transfer of dispersed donor chicken seminiferous epithelial cells into the testes of sterilized chickens resulted in limited repopulation of the seminiferous epithelium in a few tubules. By transferring spermatogonia, it is hoped that a far greater proportion of the seminiferous tubules will be repopulated with a proliferating seminiferous epithelium. Isolating spermatogonia for culture is difficult. We have identified probes that are specific for chicken (c-kit) and turkey spermatogonia (PNA, c-kit) and will use these to obtain an enriched population of spermatogonia for culturing. Initial attempts at culturing dispersed chicken seminiferous epithelial cells have been successful. After two weeks, cells have proliferated into clusters some seemingly forming a mound with a circumferential basement membrane. In addition, we have tentatively identified four spermatogonial subtypes based on cell and nuclear morphology. This line of work will continue as we seek to develop techniques for the production of transgenic poultry using spermatogonia as the target cells for transfection and transfer.