title: Cell-cycle-dependent colonization of mouse spermatogonial stem cells after transplantation into seminiferous tubules.
abstract: Spermatogonial stem cells (SSCs) migrate to the niche upon introduction into the seminiferous tubules of the testis of infertile animals. However, only 5-10% of the transplanted cells colonize recipient testes. In this study, we analyzed the impact of cell cycle on spermatogonial transplantation. We used fluorescent ubiquitination-based cell cycle indicator transgenic mice to examine the influence of cell cycle on SSC activity of mouse germline stem (GS) cells, a population of cultured spermatogonia enriched for SSCs. GS cells in the G1 phase are more efficient than those in the S/G2-M phase in colonizing the seminiferous tubules of adult mice. Cells in the G1 phase not only showed higher expression levels of GFRA1, a component of the GDNF self-renewal factor receptor, but also adhered more efficiently to laminin-coated plates. Furthermore, this cell cycle-dependency was not observed when cells were transplanted into immature pup recipients, which do not have the blood-testis barrier (BTB) between Sertoli cells, suggesting that cells in the G1 phase may passage through the BTB more readily than cells in the S/G2-M phase. Thus cell cycle status is an important factor in regulating SSC migration to the niche.
authors.affiliation: Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ishii
authors.forename: Mito
authors.initials: M
authors.lastname: Kanatsu-Shinohara
authors.forename: Takashi
authors.initials: T
authors.lastname: Shinohara
mesh_terms: D000818:Animals; D001814:Blood-Testis Barrier / Q000502:physiology; D002453:Cell Cycle / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D008297:Male; D051379:Mice; D012671:Seminiferous Tubules / Q000502:physiology*; D012708:Sertoli Cells / Q000166:cytology; D013091:Spermatogenesis / Q000502:physiology; D013093:Spermatogonia / Q000166:cytology* / Q000637:transplantation; D055153:Stem Cell Niche / Q000502:physiology*; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology