Spectrin and ankyrin like proteins in spermatids and spermatozoa of the hamster and some other mammals.

The presence of spectrin and ankyrin-like proteins was investigated during the differentiation and maturation of spermatozoa in mammalian species which have previously been studied for actin and calmodulin. These actin-binding proteins were characterized by immunoblotting and localized by immunoelectron microscopy. Neither spectrin nor ankyrin could be detected in the F-actin rich subacrosomal layer of spermatids in any species. In hamster and mouse maturing spermatids and spermatozoa, spectrin was mainly evidenced around the fibrous sheath of the flagellum whereas ankyrin was detected only in the neck. In rabbit spermatozoa, spectrin was evidenced in the outermost cytoplasmic layer of the post-acrosomal region and a light ankyrin labeling appeared in the neck. In rat, monkey and human sperm cells, these 2 proteins were not demonstrated. These results showed that as for actin there was no uniform pattern of distribution of spectrin and ankyrin among the 6 species studied.