Zona pellucida glycoprotein

Mori, E., Hedrick, J.L., Wardrip, N.J., Mori, T. and Takasaki, S. (1998) Occurrence of reducing terminal N-acetylglucosamine 3-sulfate and fucosylated outer chains in acidic N-glycans of porcine zona pellucida glycoproteins. Glycoconj J, 15,447-456. 

No sperm enzymes have yet been described which meet all of these criteria. However, acrosin satisfactorily meets the first three criteria and, with the identification of the zona pellucida glycoprotein which is a substrate for acrosin, it is now possible to approach experimentally the fourth criterion (7). 

Bleil, J.D. and Wassarman, P.M. (1983). Sperm-egg interactions in the mouse Sequence of events and induction of the acrosome reaction by a zona pellucida glycoprotein. Dev. Biol. 95 317-324. 

Dunbar, B.S., Dudkiewicz, A.B., and Bundman, D.S. (1985). Proteolysis of specific porcine zona pellucida glycoproteins by boar acrosin. Biol. Reprod. 52 619-630. 

R. J. Jackson, et al., Infertility in mice induced by a recombinant ectromelia virus expressing mouse zona pellucida glycoprotein, Biology of Reproduction, 58, 1998, 152-9 Jackson et al., 2001, note 1. 

Wassarman PM, Litscher ES. 2001. Multiple functions of mouse zona pellucida glycoprotein mZP3, the sperm receptor. Ital J Anat Embryol 106(2 Suppl 2) 21-32. 

C. H. Hokke, J. B. L. Damm, J. P. Kamerling, J. F. G. Vliegenthart, Structure of three acidic 0-linked carbohydrate chains of porcine zona pellucida glycoproteins. FEBS Lett. 1993 329, 29-34. 

The repulsive, electrostatic forces of sialic acids contribute to the rigidity of the cell surface, as was shown hy an increase in the defor-mability of sarcoma cells after enzymic removal of sialic acid residues.424 Enzymic release of sialic acids from the zona pellucida of rabbit ovum lessens the rigidity of this cell, and spermatozoa can no longer penetrate it.425 Glycoproteins on the surface of sea-urchin eggs... 

Fertilization is the fusion of the sperm and ovum. The sperm head binds to the plasma membrane of the egg (oolemma), and the entire spermatozoon enters the cytoplasm of the ovum. Only capacitated spermatozoa with intact acrosomes can enter and pass through the cumulus oophorus. The acrosome is a membrane-bound, cap-like structure covering the anterior portion of the sperm nucleus. The acrosomal reaction is the release of materials that lyse the glycoprotein coat (zona pellucida) surrounding the ovum. This is necessary for fertilization to take place. Before undergoing the acrosomal reaction, sperm go through a type of hypermotility called hyperactivation. The... 

Figure 3. A Model for Acrosin s Role in Zona Pellucida Binding and Penetration of Sperm. The model uses the m -acrosin form depicted in Figure 2. Acrosin is bound to the sperm plasma membrane (PM) via its hydrophobic domain and interacts with the egg zona pellucida (ZP) via its protease and carbohydrate binding domains. The ZP is composed of three glycoproteins which have unique polypeptide chains and both shared and unique oligosaccharide moieties. Symbols used - oligosaccharide...

The frequency of the menstrual/estrous cycle varies among species. For example, monoestrous species (e.g., dogs, cats) exhibit 1-2 cycles per year, whereas polyes-trous species (e.g., rodents, primates) exhibit more frequent cycles of shorter duration. Primordial follicles, each consisting of an oocyte surrounded by a single layer of flattened somatic cells known as granulosa cells, are recruited to become primary follicles, a transition marked by increased oocyte size, formation of a glycoprotein matrix (zona pellucida) around the oocyte, and transformation to cuboidal-shaped... 

Hamazaki, T.S., Y. Nagahama, I. Iuchi and K. Yamagami. A glycoprotein from the liver constitutes the inner layer of the egg envelope (zona pellucida interna) of the fish, Oryzias latipes. Dev. Biol. 133 101-110, 1989. 

Sperm penetrate the zona pellucida only after completion of the acrosome reaction. A similar process occurs in nonmammalian species, where sperm must penetrate the vitelline coat. In abalone this is accomplished by release of lysin, an acrosomal protein that disperses the vitelline coat by a noncatalytic mechanism (Lewis et al., 1982 Shaw et al., 1993). In contrast, the generally accepted model for mammalian sperm penetration of the zona pellucida is the acrosin hypothesis in which proteolysis of zona pellucida matrix glycoproteins by acrosin, the acrosomal serine esterase, plays a trailblazing role in the sperm penetration process (Yanag-... 

Results obtained" from the reaction of periodate with oligosaccharide structures in erythropoietin are consistent with the proposal that antibodies directed against the recombinant hormone are anti-carbohydrate . That oligosaccharide sequences are involved in the binding of human spermatozoa to a glycoprotein of the zona pellucida, is indicated " " by a marked decrease in binding that accompanies selective periodate oxidation of terminal sialic acid residues of the glycoprotein. 

Fibromodulin in cartilage and osteoadherin in bone are also modified with A-linked KS chains, as is the PZP3 protein from zona pellucida [14-16]. The cartilage proteoglycan aggrecan was recently shown to contain 2-3 A-linked KS chains in addition to the 20 or more 0-linked KS attachment sites [17]. KSI was also found in dermis of the Pacific mackerel [18]. In addition to these clearly defined examples of KSI, A-linked polylactosamine is a component of numerous cell surface and extracellular glycoproteins, many of these sulfated. It seems likely that future studies will add to the list of KSI-bearing compounds. 

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