Dynamic expression of the prion-like protein Doppel in ovine testicular tissue

• Published in: International journal of andrology Vol. 29; no. 3; pp. 400 - 408
• Main Authors: Espenes, Arild, Harbitz, Ingrid, Skogtvedt, Susan, Fuglestveit, Ragnhild, Berg, Kjell A., Dick, Gunnar, Krogenaes, Anette, Tranulis, Michael A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.06.2006; Blackwell
• Subjects: Animals; Biological and medical sciences; Blotting, Western; Doppel; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental; Glycosylation; Gynecology. Andrology. Obstetrics; Infertility, Male - physiopathology; Male; Male genital diseases; Mammalian male genital system; Medical sciences; ovine; Phagocytosis - physiology; Prions - genetics; Prions - metabolism; RNA, Messenger - analysis; Seminiferous Epithelium - cytology; Seminiferous Epithelium - physiology; seminiferous tubules; Sexual Maturation; Sheep; Spermatids - physiology; Spermatozoa - physiology; stage-specific expression; testicle; Vertebrates: reproduction; Doppel; seminiferous tubules; Male genital duct; ovine; Testicle; stage- specific expression; Male genital system; Vertebrata; Reproduction; Mammalia; Animal; Seminiferous tubule; Sheep; Prion; Artiodactyla; Ungulata
• ISSN: 0105-6263; 1365-2605
• DOI: 10.1111/j.1365-2605.2005.00618.x

Summary 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.