title: Nature of the spermatogenic arrest in Dazl -/- mice.
abstract: Dazl encodes an RNA-binding protein essential for spermatogenesis. Mice that are deficient for Dazl are infertile, lacking any formation of spermatozoa, and the only germ cells present are spermatogonia and a few spermatocytes. To gain more insight regarding the timing of the spermatogenic arrest in Dazl -/- mice, we studied the spermatogonial cell types present in testis sections and in seminiferous tubular whole mounts. Most of the seminiferous tubular cross-sections contained A spermatogonia as the most advanced cell type, with only very few containing cells up to pachytene spermatocytes. Both 5-bromodeoxy-uridine incorporation and mitotic index indicated that the remaining A spermatogonia were actively proliferating. C-kit immunohistochemical studies showed that most of the A spermatogonia were positively stained for the c-Kit protein ( approximately 80%). The clonal composition of the A spermatogonia in tubular whole mounts indicated these cells to be A(single) (A(s)), A(paired) (A(pr)), and A(aligned) (A(al)) spermatogonia. It is concluded that the prime spermatogenic defect in the Dazl -/- mice is a failure of the great majority of the A(al) spermatogonia to differentiate into A(1) spermatogonia. As a result, most seminiferous tubules of Dazl -/- mice only contain actively proliferating A(s), A(pr), and A(al) spermatogonia, with cell production being equaled by apoptosis of these cells.
authors.affiliation: Department of Cell Biology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors.forename: B H
authors.initials: BH
authors.lastname: Schrans-Stassen
authors.forename: P T
authors.initials: PT
authors.lastname: Saunders
authors.forename: H J
authors.initials: HJ
authors.lastname: Cooke
authors.forename: D G
authors.initials: DG
authors.lastname: de Rooij
mesh_terms: D000818:Animals; D017209:Apoptosis; D007150:Immunohistochemistry; D007248:Infertility, Male / Q000235:genetics* / Q000473:pathology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008940:Mitotic Index; D011506:Proteins / Q000235:genetics* / Q000502:physiology; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D016601:RNA-Binding Proteins; D012671:Seminiferous Tubules / Q000473:pathology; D012708:Sertoli Cells / Q000473:pathology; D013090:Spermatocytes / Q000473:pathology; D013091:Spermatogenesis / Q000235:genetics*; D013093:Spermatogonia / Q000473:pathology; D013737:Testis / Q000473:pathology
chemical_list: C101358:DAZL protein, human; D011506:Proteins; D016601:RNA-Binding Proteins; D019009:Proto-Oncogene Proteins c-kit