title: Germ line stem cell competition in postnatal mouse testes.
abstract: Niche is believed to affect stem cell behavior. In self-renewing systems for which functional transplantation assays are available, it has long been assumed that stem cells are fixed in the niche and that ablative treatments to remove endogenous stem cells are required for successful donor engraftment. Our results demonstrate that enriched populations of donor stem cells can produce long-lasting spermatogenic colonies in testes of immature and mature, nonablated mice, albeit at a lower frequency than in ablated mice. Colonization of nonablated recipient testes by neonate, pup, and cryptorchid adult donor spermatogonial stem cells demonstrates that competition for niche begins soon after birth and that endogenous stem cells influence the degree and pattern of donor cell colonization. Thus, a dynamic relationship between stem cell and niche exists in the testis, as has been suggested for hematopoiesis. Therefore, similar competitive properties of donor stem cells may be characteristic of all self-renewing systems.
authors.affiliation: Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3850 Baltimore Avenue, Philadelphia, PA 19104, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shinohara
authors.forename: Kyle E
authors.initials: KE
authors.lastname: Orwig
authors.forename: Mary R
authors.initials: MR
authors.lastname: Avarbock
authors.forename: Ralph L
authors.initials: RL
authors.lastname: Brinster
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D002066:Busulfan / Q000494:pharmacology; D003456:Cryptorchidism / Q000473:pathology; D005854:Germ Cells / Q000502:physiology* / Q000637:transplantation; D008297:Male; D051379:Mice; D012671:Seminiferous Tubules / Q000166:cytology / Q000187:drug effects; D013091:Spermatogenesis / Q000502:physiology; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000502:physiology*; D013737:Testis / Q000166:cytology* / Q000254:growth & development* / Q000502:physiology
chemical_list: D000477:Alkylating Agents; D002066:Busulfan