title: Expression of CD46 in developing rat spermatozoa: ultrastructural localization and utility as a marker of the various stages of the seminiferous tubuli.
abstract: Identification of the various stages of the seminal tubule epithelium that are important in spermatogenesis in humans and rodents requires considerable expertise for analysis of ultrastructural appearance under light microscopy. Few good stage-specific markers have been reported to facilitate the process. We recently described characterization of the expression of CD46 (membrane cofactor protein) in the rat using a novel monoclonal antibody. Expression of CD46 was restricted to spermatozoa and their immediate precursors in the testis. In the present study, we used a combination of morphological analyses, known acrosome markers, actin staining, direct nuclear staining, and staining for CD46 to delineate precisely the subcellular location of CD46. Staining of CD46 colocalized with known acrosome markers in late spermatids and mature spermatozoa and was confirmed by electron microscopy to be acrosome-restricted. Expression was first detected in step 7 spermatids, whereas known markers were not expressed until step 9. The CD46 staining pattern differed through spermatid development, and distinct patterns of staining could be identified that, when combined with 4'-6-diamino-2-phenylindole-2HCl nuclear staining, enabled the accurate staging of the seminiferous tubule epithelium in different profiles. This detailed description of the spatiotemporal expression patterns of CD46 provides a valuable tool for analysis of spermatogenesis in the rat. Furthermore, this information will aid ongoing studies regarding the roles of CD46 in acrosome-related spermatozoal functions.
authors.affiliation: Complement Biology Group, Department of Medical Biochemistry and Immunology, School of Medicine, Cardiff University, Henry Wellcome Building, Heath Park, Cardiff, CF14 4XN, United Kingdom.
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizuno
authors.forename: Claire L
authors.initials: CL
authors.lastname: Harris
authors.forename: Norihiko
authors.initials: N
authors.lastname: Suzuki
authors.forename: Seiichi
authors.initials: S
authors.lastname: Matsuo
authors.forename: B Paul
authors.initials: BP
authors.lastname: Morgan
mesh_terms: D000177:Acrosome / Q000378:metabolism / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D004396:Coloring Agents; D004801:Eosine Yellowish-(YS); D005456:Fluorescent Dyes; D006416:Hematoxylin; D007211:Indoles; D008297:Male; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D051381:Rats; D017208:Rats, Wistar; D012670:Seminiferous Epithelium / Q000166:cytology / Q000502:physiology*; D013087:Spermatids / Q000378:metabolism / Q000648:ultrastructure; D013091:Spermatogenesis / Q000502:physiology*; D013094:Spermatozoa / Q000378:metabolism* / Q000648:ultrastructure*; D013194:Staining and Labeling
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015415:Biomarkers; C497860:Cd46 protein, rat; D004396:Coloring Agents; D005456:Fluorescent Dyes; D007211:Indoles; D051916:Membrane Cofactor Protein; D008562:Membrane Glycoproteins; C007293:DAPI; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin