The Molecular Basis of Sea Urchin Gamete Interactions at the Egg Plasma Membrane

Foltz, Kathleen R.; Lennarz, William J.

doi:10.1006/dbio.1993.1167

Cited by 83 publications

(28 citation statements)

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“…the acrosome reaction). After sperm have penetrated the egg coat, direct gamete cell-cell interactions can occur (Foltz and Lennarz, 1993;Kaji and Kudo, 2004). In mammals, sperm proteins that mediate egg binding and fusion are thought to include the surface-associated protein DE (Ellerman et al, 2002), the immunoglobulin-like protein Izumo (Inoue et al, 2005), and the sperm ADAM proteins (fertilin α, fertilin β and cyritestin) (Evans, 2001).…”

Section: Introductionmentioning

confidence: 99%

TheCaenorhabditis elegans spe-38gene encodes a novel four-pass integral membrane protein required for sperm function at fertilization

et al. 2005

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A mutation in the Caenorhabditis elegans spe-38 gene results in a sperm-specific fertility defect. spe-38 sperm are indistinguishable from wild-type sperm with regards to their morphology, motility and migratory behavior. spe-38 sperm make close contact with oocytes but fail to fertilize them. spe-38 sperm can also stimulate ovulation and engage in sperm competition. The spe-38 gene is predicted to encode a novel four-pass (tetraspan) integral membrane protein. Structurally similar tetraspan molecules have been implicated in processes such as gamete adhesion/fusion in mammals, membrane adhesion/fusion during yeast mating, and the formation/function of tight-junctions in metazoa. In antibody localization experiments, SPE-38 was found to concentrate on the pseudopod of mature sperm, consistent with it playing a direct role in gamete interactions.

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Section: Introductionmentioning

confidence: 99%

TheCaenorhabditis elegans spe-38gene encodes a novel four-pass integral membrane protein required for sperm function at fertilization

et al. 2005

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“…Once spawned, the sperm must find and interact with an egg of the correct species. A further event necessary for successful fertilization is induction of the acrosome reaction in the sperm (3,4), which involves fusion of the acrosomal vesicle membrane with the plasma membrane. This results in exocytosis of the vesicle contents, which include proteases and bindin.…”

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confidence: 99%

Sulfated Polysaccharides from the Egg Jelly Layer Are Species-specific Inducers of Acrosomal Reaction in Sperms of Sea Urchins

Alves

Mulloy

Diniz

et al. 1997

Journal of Biological Chemistry

168

121

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We have characterized the fine structure of sulfated polysaccharides from the egg jelly layer of three species of sea urchins and tested the ability of these purified polysaccharides to induce the acrosome reaction in spermatozoa. The sea urchin Echinometra lucunter contains a homopolymer of 2-sulfated, 3-linked ␣-L-galactan. The species Arbacia lixula and Lytechinus variegatus contain linear sulfated ␣-L-fucans with regular tetrasaccharide repeating units. Each of these sulfated polysaccharides induces the acrosome reaction in conspecific but not in heterospecific spermatozoa. These results demonstrate that species specificity of fertilization in sea urchins depends in part on the fine structure of egg jelly sulfated polysaccharide.Successful fertilization by free-spawning organisms such as sea urchins can occur only if a series of constraints are overcome before the sperm ever makes contact with the egg (1). First, males and females must synchronize the time of release of their gametes (2). Once spawned, the sperm must find and interact with an egg of the correct species. A further event necessary for successful fertilization is induction of the acrosome reaction in the sperm (3, 4), which involves fusion of the acrosomal vesicle membrane with the plasma membrane. This results in exocytosis of the vesicle contents, which include proteases and bindin. Concomitantly, actin in the subacrosomal region of the sperm polymerizes and causes extension of the tip of the sperm. As a consequence of these two events, bindin is localized to the outside of the tip of the process where it can then interact with an egg protein (3, 4).The acrosome reaction is induced when the sperms contact the egg jelly layer. The sea urchin egg is surrounded by a transparent gelatinous layer composed mainly of sulfated fucan, sialoprotein, and other glycoproteins or peptides (5). Previous attempts to identify the acrosome reaction inducer in sea urchin egg jelly have suggested that all the activity resides in the sulfated fucan (6, 7). In addition, these authors suggested that the jelly coat preparations of some species of sea urchins are totally species-specific and induce the acrosome reaction only in homologous sperm. On the basis of these observations, it was suggested that the specificity of induction of the acrosome reaction might reside in structural differences in the carbohydrate linkages and/or location and degree of sulfation of the polysaccharide (6, 7). Recent studies suggest that a glycoprotein or peptide, tightly associated with the sulfated fucan, was also involved in acrosome reaction induction (8 -11).In this study, we isolated, purified, and characterized the fine structure of the sulfated polysaccharides from the egg jelly coat of three species of sea urchins. These compounds have simple, well-defined repeating structures that from each species present a particular pattern of sulfate substitution. Purified polysaccharide from the egg jelly induces the acrosome reaction in sperm from the same species of sea urchin and not f...

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“…During fertilization in many animals, including sea urchins and mammals, outer investments of the egg trigger the exocytosis of a single exocytotic vesicle in sperm, the acrosomal vesicle (1)(2)(3). This process, the acrosome reaction, exposes the sperm membrane that will fuse with the egg plasma membrane to initiate development.…”

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confidence: 99%

Increased Association of Synaptosome-associated Protein of 25 kDa with Syntaxin and Vesicle-associated Membrane Protein following Acrosomal Exocytosis of Sea Urchin Sperm

Schulz

Sasaki

Vacquier

1998

Journal of Biological Chemistry

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Synaptosomal-associated protein of 25 kDa (SNAP-25) is a palmitoylated integral membrane protein expressed almost exclusively in neuronal and neuroendocrine tissues. This protein forms a ternary complex with vesicleassociated membrane protein (VAMP) and syntaxin, which is thought to regulate the fusion of plasma and vesicle membranes during exocytosis. We report the identification of SNAP-25 expressed in sea urchin sperm. Sea urchin SNAP-25 shares greater identity with mammalian SNAP-25 than with mammalian SNAP-23, a ubiquitously expressed homologue believed to regulate membrane fusion in non-neuronal tissues. Sea urchin sperm contain a single exocytotic vesicle, the acrosomal vesicle, whose contents are exposed during the acrosome reaction. Fusion of the plasma membrane with the acrosomal vesicle membrane at multiple points (vesiculation) results in the release of SNAP-25 with the shed acrosome reaction vesicles. A complex containing SNAP-25, syntaxin, and VAMP is present in sperm, as detected by affinity chromatography and immunoprecipitation. Although this complex is present prior to the acrosome reaction, the amount of complex increases over 4-fold following acrosomal exocytosis. These findings support the involvement of SNAP-25 in the invertebrate sperm acrosome reaction, possibly through increased association with VAMP and syntaxin driving the fusion of plasma and acrosomal membranes.

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The Molecular Basis of Sea Urchin Gamete Interactions at the Egg Plasma Membrane

Cited by 83 publications

References 0 publications

TheCaenorhabditis elegans spe-38gene encodes a novel four-pass integral membrane protein required for sperm function at fertilization

TheCaenorhabditis elegans spe-38gene encodes a novel four-pass integral membrane protein required for sperm function at fertilization

Sulfated Polysaccharides from the Egg Jelly Layer Are Species-specific Inducers of Acrosomal Reaction in Sperms of Sea Urchins

Increased Association of Synaptosome-associated Protein of 25 kDa with Syntaxin and Vesicle-associated Membrane Protein following Acrosomal Exocytosis of Sea Urchin Sperm

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