ConA-binding proteins of the sperm surface are conserved through evolution and in sperm maturation.
Lectin-binding glycoconjugates present on the surface of spermatozoa are believed to play a crucial role in sperm maturation, capacitation, acrosome reaction, or sperm-egg interaction. We have studied ConA-binding surface proteins on spermatozoa from different mammalian species. First, ConA-binding proteins were isolated from boar spermatozoa by affinity chromatography. ConA-binding ability was confirmed by Enzyme-linked Lectin assay (ELLA). Monoclonal (MAb436/10) and polyclonal antibodies were raised against chromatography fractions containing purified ConA-binding proteins of boar spermatozoa. MAb436/10 (IgG2a) recognizes a 40 kD ConA-binding antigen. Indirect immunofluorescence on fixed and unfixed boar spermatozoa with MAb436/10 indicated a plasma membrane localization of antigen 436/10 in the acrosomal macrodomain. Interspecies cross-reactivity with MAb436/10 was found by whole cell ELISA and immunocytochemistry. MAb436/10 cross-reacted with human, horse, guinea-pig, bull, and ram spermatozoa in both assays. Expression of ConA-binding antigen 436/10 on guinea pig sperm surface was detectable during spermiogenesis and in early stages of sperm maturation. Change of regionalization of the antigen did not occur during the epididymal passage. ConA-binding antigen 436/10 was also detectable in testis and caudal segments of the epididymis. These findings suggest that ConA-binding proteins located in the acrosomal region are highly conserved through evolution as well as in sperm maturation indicating an important role for the physiology of spermatozoa.
Runnebaum
I B
IB
Department of Obstetrics and Gynecology, University of Ulm, Germany.
Schill
W B
WB
Töpfer-Petersen
E
E
D000177:Acrosome / Q000378:metabolism; D000818:Animals; D005075:Biological Evolution; D002417:Cattle; D003208:Concanavalin A / Q000378:metabolism*; D003429:Cross Reactions; D004822:Epididymis / Q000378:metabolism; D005260:Female; D006168:Guinea Pigs; D006736:Horses; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D011485:Protein Binding; D012756:Sheep; D013079:Sperm Maturation; D013094:Spermatozoa / Q000378:metabolism*; D013552:Swine; D013737:Testis / Q000378:metabolism
D008562:Membrane Glycoproteins; D003208:Concanavalin A