title: Dynamic expression of the prion-like protein Doppel in ovine testicular tissue.
abstract: Transgenic knockout of the gene encoding the prion-like protein Doppel (Dpl) leads to male infertility in mice. The precise role of Dpl in male fertility is still unclear, but sperm from Dpl-deficient mice appear to be unable to undergo the normal acrosome reaction that is necessary to penetrate the zona pellucida of the ovum. We have investigated the expression pattern and some biochemical properties of Dpl in sheep testicular tissue and spermatozoa. Neither the Dpl protein nor its mRNA was detected in pre-pubertal sheep testis. This was in contrast to the findings in adult rams where both Dpl mRNA and protein were present. The molecular mass and glycosylation pattern of sheep Dpl were similar to that of mice Dpl. The Dpl protein was detected in the seminiferous epithelium during the two final (7 and 8) and the two initial (1 and 2) stages of the spermatogenic cycle in a characteristic pattern. In stage 8, an intense brim of granular Dpl-immunoreactivity associated with maturation phase spermatids was observed, while after the release of spermatozoa in stages 1 and 2, the Dpl-staining was disseminated more diffusely in the epithelium, reaching the basal lamina. From stage 3 to stage 6, Dpl-immunoreactivity could not be detected, indicating that the Dpl protein had disappeared between stages 2 and 3. Dpl was not detected on ejaculated spermatozoa. These patterns of staining indicate that Dpl is enriched in residual bodies, which are phagocytosed and destroyed by Sertoli cells after release of sperm into the lumen of the seminiferous tubule.
authors.affiliation: Department of Basic Sciences and Aquatic Medicine, Norwegian School of Veterinary Science, Oslo, Norway.
authors.forename: Arild
authors.initials: A
authors.lastname: Espenes
authors.forename: Ingrid
authors.initials: I
authors.lastname: Harbitz
authors.forename: Susan
authors.initials: S
authors.lastname: Skogtvedt
authors.forename: Ragnhild
authors.initials: R
authors.lastname: Fuglestveit
authors.forename: Kjell A
authors.initials: KA
authors.lastname: Berg
authors.forename: Gunnar
authors.initials: G
authors.lastname: Dick
authors.forename: Anette
authors.initials: A
authors.lastname: Krogenaes
authors.forename: Michael A
authors.initials: MA
authors.lastname: Tranulis
mesh_terms: D000818:Animals; D015153:Blotting, Western; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D006031:Glycosylation; D007248:Infertility, Male / Q000503:physiopathology; D008297:Male; D010587:Phagocytosis / Q000502:physiology; D011328:Prions / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D012670:Seminiferous Epithelium / Q000166:cytology / Q000502:physiology*; D012741:Sexual Maturation; D012756:Sheep; D013087:Spermatids / Q000502:physiology; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D011328:Prions; D012333:RNA, Messenger