Developmentally Regulated Oligosaccharides in Mouse Spermatogenic Cells

Mouse spermatogenic cells were separated into four populations, pachytene spermatocytes, round spermatids, elongated spermatids, and residual bodies. Each cell population was metabolically labeled with [3H]galactose, [3H]glucosamine, or [3H]fucose. Glycopeptides were prepared from the radiolabeled glycoproteins by pronase digestion and fractionated by serial lectin affinity chromatography and gel filtration. The presence of O-linked oligosaccharides was assessed by pronase digestion of [3H]galactose-labeled glycoproteins, exclusion of the radiolabeled glycopeptides from a ConA-Sepharose column, gel filtration, and treatment with alkaline borohydride. This analysis reveals that a large proportion of [3H]galactose-labeled oligosaccharides (47-52%) are O-linked structures, while the majority (80-90%) of [3H]fucose-labeled oligosaccharides are N-linked. The proportions of triantennary, biantennary, oligomannose, and hybrid oligosaccharides linked to asparagine vary with the cell populations. Furthermore, in round spermatids, but not in the other cell populations, a relatively large proportion (15%) of [3H]glucosamine-labeled oligosaccharides consists of terminal O-linked N-acetyl-glucosamine. Taken together these data show that each spermatogenic cell population contains a unique complement of oligosaccharide structures that could play an important role as differentiation signals in the interactions among these cells and/or with Sertoli cells.