Binding of a major secretory protein from bull seminal vesicles to bovine spermatozoa

Abstract

The seminal vesicles synthesize in an androgen-dependent manner a neutral protein of 13.5 kDa molecular weight that makes up about 40% of their secretion ("major protein"). An antiserum against this protein raised in rabbits was used to localize the antigen within the seminal vesicles. In addition to intraluminal secretion of the seminal vesicles and the ampulla of the vas deferens, ejaculated and ampullary spermatozoa revealed an intense immunoreaction, which was restricted to the neck region of the sperm head and the middle piece, while the principal piece of the tail as well as the sperm head were devoid of immunoreactive material. Comparison of spermatozoa taken from the tail of the epididymis with ampullary spermatozoa showed that about 90% of the latter, but only 10-20% of the former presented this distributional pattern of immunoreactive sites. Epididymal epithelium as well as calf seminal vesicle epithelium showed no immunoreactivity with major protein antiserum. Using a pre-embedding staining technique with gold-labeled primary or secondary antibodies, respectively, no immunostaining could be achieved at the ultrastructural level. Incubation experiments of epididymal spermatozoa in EGTA-containing solutions in the absence of calcium resulted in a gradual labilization and eventual loss of the plasma membrane of the sperm middle piece. After removal of (at least part of) the plasma membrane, bound major protein could be visualized immunohistochemically close to the mitochondria of the middle piece using a gold-labeled primary or secondary antibody. The acceptor site for major protein therefore seems to reside inside the plasma membrane of the sperm middle piece.(ABSTRACT TRUNCATED AT 250 WORDS)

Bovine seminal PDC-109 protein: An overview of biochemical and functional properties

“…Bovine seminal plasma proteins bind to the surface of plasma membrane of spermatozoa (Aumuller et al, 1988), more specifically, to the mid piece of sperm once they pass the ampulla of the vas deferens during emission (Sanchez-Luengo et al, 2004). Indirect immunofluorescent labeling of fixed ejaculated sperm with anti-PDC-109 antiserum revealed labeling over the acrosomal region of the sperm head, which is the region known to bind to oviductal epithelium (Gwathmey et al, 2003).…”

“…phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatic acid and cardiolipin (Desnoyers and Manjunath, 1992). In addition to their heparin-and lipid-binding activities, the BSP proteins interact with a variety of ligands including different collagens (type I, II, IV, V), fibrinogen, apolipoprotein A1, apolipoprotein A1/high-density lipoprotein complexes, (Aumuller et al, 1988), biding to choline phospholipids (Desnoyers and Manjunath, 1992), binding to mid piece of sperm and sperm motility (Sanchez-Luengo et al, 2004), oviductal sperm reservoir (Gwathmey et al, 2003), capacitation and AR (Therien et al, 1995) and cryoinjury (Therien et al, 1999). and calmodulin (Therien et al, 1995), in free form or associated with HDL (Manjunath et al, 1989).…”

“…Bovine PDC-109 protein has been purified and characterized by various workers (Esch et al, 1983;Aumuller et al, 1988;Calvete et al, 1994). isolated PDC-109 protein, BSP-A3, and BSP-30-kDa proteins using gelatin-agarose affinity chromatography.…”

Localization and structural characterization of an oligosaccharide O‐linked to bovine PDC‐109 Quantitation of the glycoprotein in seminal plasma and on the surface of ejaculated and capacitated spermatozoa

“…The mechanism of this process remains to be elucidated, however. Thus, Aumtiller et al [20] have reported that Major Protein (PDC-109) binds to the midpiece of spermatozoa to a 65-67 kDa protein duplet and appears to initiate hyperactive sperm motility. On the other hand, Desnoyers and Manjunath [6] have shown that BSP-Al (PDC-109) binds specifically to phospholipids which contain the phosphorylcholine group, and proposed that this interaction may play a important role in the membrane modification that occurs during capacitation.…”

Two Rat Middle-Piece Coating Antigens Are Lost upon in vitro Capacitation

“…For example, alterations in flagellar movements can be observed when soluble fac tors arc attached to or lost from the cells [2], Sperm-coating antigens restricted to the middie-piece domain have been suggested to in fluence the motility of golden hamster [52] and bovine [24] spermatozoa. In the rat.…”