title: Id4 Marks Spermatogonial Stem Cells in the Mouse Testis.
abstract: Mammalian spermatogenesis is a classic adult stems cell-dependent process, supported by the self-renewal and differentiation of spermatogonial stem cells (SSCs). However, the identification of SSCs and elucidation of their behaviors in undisturbed testis has long been a big challenge. Here, we generated a knock-in mouse model, Id4-2A-CreERT2-2A-tdTomato, which allowed us to mark Id4-expressing (Id4(+)) cells at different time points in situ and track their behaviors across distinct developmental stages during steady-state and regenerating spermatogenesis. We found that Id4(+) cells continue to produce spermatogonia, spermatocytes and sperm in mouse testis, showing they are capable of self-renewal and have differentiation potential. Consistent with these findings, ablation of Id4(+) cells in mice results in a loss of spermatogenesis. Furthermore, developmental fate mapping reveals that Id4(+) SSCs originate from neonate Id4(+) gonocytes. Therefore, our results indicate that Id4 marks spermatogonial stem cells in the mouse testis.
authors.forename: Feng
authors.initials: F
authors.lastname: Sun
authors.forename: Qing
authors.initials: Q
authors.lastname: Xu
authors.forename: Danfeng
authors.initials: D
authors.lastname: Zhao
authors.forename: Charlie
authors.initials: C
authors.lastname: Degui Chen
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000235:genetics / Q000378:metabolism*; D051796:Inhibitor of Differentiation Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D013091:Spermatogenesis / Q000502:physiology*; D013093:Spermatogonia / Q000166:cytology / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D013737:Testis / Q000166:cytology / Q000378:metabolism*
chemical_list: D000943:Antigens, Differentiation; C086479:Idb4 protein, mouse; D051796:Inhibitor of Differentiation Proteins