Expression of CD46 in Developing Rat Spermatozoa: Ultrastructural Localization and Utility as a Marker of the Various Stages of the Seminiferous Tubuli1

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.

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 2: Changes in spermatid organelles associated with development of spermatozoa

“…Cd46-null mice are fertile, but the fertilizing ability of males is enhanced as the average number of pups is significantly greater and spontaneMicroscopy Research and Technique ous acrosome reaction doubles in frequency . Expression is first detected in the acrosome of step 7 spermatids, with distinct patterns of staining being identified through spermatid development (Mizuno et al, 2005 T2-222] is essentially restricted to the testis. Cd59b localizes to the sperm acrosome and its absence is accompanied by reduced motility and progressive loss of fertility with age.…”

RFamide-Related Peptide and Messenger Ribonucleic Acid Expression in Mammalian Testis: Association with the Spermatogenic Cycle

“…Captured images were examined for triple labeling using Zeiss LSM Browser and Photoshop software. Seminiferous epithelial stages were distinguished by the morphology of the cell nuclear label revealed by DAPI(31,32).…”