Fucoidin inhibits attachment of guinea pig spermatozoa to the zona pellucida through binding to the inner acrosomal membrane and equatorial domains

1984 ◽  
Vol 153 (2) ◽  
pp. 363-373 ◽  
Author(s):  
T.T.F. Huang ◽  
R. Yanagimachi
Development ◽  
1990 ◽  
Vol 109 (1) ◽  
pp. 41-50
Author(s):  
R. Jones ◽  
R.M. Williams

Binding of guinea-pig spermatozoa to the zona pellucida of homologous eggs has been reported to involve ‘receptors’ on the inner acrosomal membrane (Huang et al. 1981). These receptors can be blocked by sulphated polysaccharides such as fucoidan (Huang and Yanagimachi, 1984). The aims of the present investigation were to identify these putative zona receptors using 125I-fucoidan as a probe and examine their mechanism of recognition. Results show that 125I-fucoidan binds to several proteins extracted from guinea-pig spermatozoa with molecular masses of 95, 60, 48, 34, 30 and 18–20 × 10(3) (K) on SDS-PAGE. The 48K, 34K and 30K components represent proacrosin and two forms of acrosin, respectively. 125I-zona pellucida glycoproteins also bound strongly to the 48K, 34K and 30K sperm proteins. The other high and low mass binding proteins were not positively identified but cytochemical experiments with fluoresceinamine-fucoidan and FITC-soybean trypsin inhibitor indicate that they are intraacrosomal. The mechanism of binding of 125I-fucoidan to proacrosin/acrosin (and also the 95K, 60K and 18K-20K components) involves multiple sulphate groups on the polysaccharide in a specific orientation to allow them to interact with basic residues on the protein. It is suggested that guinea-pig spermatozoa retain sufficient proacrosin/acrosin bound to the inner acrosomal membrane after the acrosome reaction to mediate binding to the zona pellucida and that functionally proacrosin is analogous to sea urchin binding.


Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 141-149 ◽  
Author(s):  
S. Mortillo ◽  
P.M. Wassarman

Egg zona pellucida glycoproteins mZP3 and mZP2 serve as primary and secondary sperm receptors, respectively, during initial stages of fertilization in mice [Wassarman (1988) A. Rev. Biochem. 57, 415–442]. These receptors interact with complementary egg-binding proteins (EBPs) located on the sperm surface to support species-specific gamete adhesion. Results of whole-mount autoradiographic experiments suggest that purified egg mZP3 and mZP2 bind preferentially to acrosome-intact (AI) and acrosome-reacted (AR) sperm heads, respectively [Bleil and Wassarman (1986) J. Cell Biol. 102, 1363–1371]. Here, we used purified egg mZP2, egg mZP3 and fetuin, which were coupled directly to colloidal gold (‘gold-probes’), to examine binding of these glycoproteins to membrane compartments of AI and AR sperm by transmission electron microscopy. mZP3 gold-probes were found associated primarily with plasma membrane overlying the acrosomal and post-acrosomal regions of AI sperm heads. They were also found associated with plasma membrane overlying the post-acrosomal region of AR sperm heads. mZP2 gold-probes were found associated primarily with inner acrosomal membrane of AR sperm heads, although some gold was associated with outer acrosomal membrane of AI sperm that had holes in plasma membrane overlying the acrosome. Fetuin gold-probes, used to assess background levels of binding, were bound at relatively low levels to plasma membrane and inner acrosomal membrane of AI and AR sperm, respectively. None of the gold-probes exhibited significant binding to sperm tails, or to red blood cells and residual bodies present in sperm preparations. These results provide further evidence that mZP2 and mZP3 bind preferentially to heads of AR and AI sperm, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)


1990 ◽  
Vol 111 (6) ◽  
pp. 2939-2949 ◽  
Author(s):  
W F Lathrop ◽  
E P Carmichael ◽  
D G Myles ◽  
P Primakoff

Sperm binding to the egg zona pellucida in mammals is a cell-cell adhesion process that is generally species specific. The guinea pig sperm protein PH-20 has a required function in sperm adhesion to the zona pellucida of guinea pig eggs. PH-20 is located on both the sperm plasma membrane and acrosomal membrane. We report here the isolation and sequence of a full-length cDNA for PH-20 (available from EMBL/GenBank/DDBJ under accession number X56332). The derived amino acid sequence shows a mature protein of 468 amino acids containing six N-linked glycosylation sites and twelve cysteines, eight of which are tightly clustered near the COOH terminus. The sequence indicates PH-20 is a novel protein with no relationship to the mouse sperm adhesion protein galactosyl transferase and no significant homology with other known proteins. The two PH-20 populations, plasma membrane and acrosomal membrane, could arise because one form of PH-20 is encoded and differentially targeted at different spermatogenic stages. Alternatively, two different forms of PH-20 could be encoded. Our evidence thus far reveals only one sequence coding for PH-20: Southern blots of guinea pig genomic DNA indicated there is a single PH-20 gene, Northern blots showed a single size PH-20 message (approximately 2.2 kb), and no sequence variants were found among the sequenced cDNA clones. Cross-species Southern blots reveal the presence of a homologue of the PH-20 gene in mouse, rat, hamster, rabbit, bovine, monkey, and human genomic DNA, showing the PH-20 gene is conserved among mammals. Since genes for zona glycoproteins are also conserved among mammals, the general features of sperm and zona proteins involved in mammalian sperm-egg adhesion may have been evolutionarily maintained. Species specificity may result from limited changes in these molecules, either in their binding domains or in other regions that affect the ability of the binding domains to interact.


1985 ◽  
Vol 101 (6) ◽  
pp. 2239-2244 ◽  
Author(s):  
P Primakoff ◽  
H Hyatt ◽  
D G Myles

After the acrosome reaction, the PH-20 surface antigen of guinea pig sperm migrates from its original location on the posterior head surface to a new location on the inner acrosomal membrane (Myles, D.G., and P. Primakoff, 1984, J. Cell Biol., 99:1634-1641). We have isolated three monoclonal antibodies (MAbs) of the IgG1 subclass, PH-20, PH-21, and PH-22, that bind to the PH-20 antigen. The PH-20 MAb strongly inhibited (approximately 90%) sperm binding to the guinea pig egg zona pellucida at saturating antibody concentrations (greater than 20 micrograms/ml). Half-maximal inhibition of sperm binding to the zona was obtained with approximately 2 micrograms/ml PH-20 MAb. The PH-21 MAb at saturating concentration (50 micrograms/ml) partially inhibited (approximately 45%) sperm-zona binding, and the PH-22 MAb (50 micrograms/ml) did not inhibit (0%) sperm-zona binding. Essentially the same amounts of the three MAbs were bound to sperm under the conditions where inhibition (PH-20, PH-21) or no inhibition (PH-22) of sperm-zona binding was observed, which indicates that the different levels of inhibition did not arise from different levels of MAb binding. Competition binding assays with 125I-labeled MAbs showed that PH-21 binding to sperm was not affected by the binding of PH-20 or PH-22. However, that PH-20 and PH-22 blocked each other's binding to sperm suggests that their recognized determinants may be relatively close to one another. The results indicate that the migrating PH-20 antigen has a required function in sperm binding to the zona pellucida and that the PH-20 MAb affects is active site.


1979 ◽  
Vol 27 (4) ◽  
pp. 857-866 ◽  
Author(s):  
P P Le Bouteiller ◽  
F Toullet ◽  
S Righenzi ◽  
G A Voisin

Three guinea pig spermatozoal autoantigens S, P and T, each one able to induce autoimmune aspermatogenic orchiepididymitis and autoantibodies, were ultrastructurally localized in male germinal cells by immunoperoxidase techniques. Both living and prefixed sectioned cell preparations were treated and examined. Fab antibody fragments were used to study intracellular antigens (whole antibodies were inefficient). Water-soluble S and P autoantigens were found in acrosomal structures in the same sites: proacrosomal and acrosomal granules of the young spermatids, on the head caps of spermatids and acrosomal cap of spermatozoa, along the inner and outer acrosomal membranes and in the outer zone of the acrosomal matrix of the same cells. S was never found in the inner zone of spermatid or spermatozoa acrosomes, while P was present in this inner zone, but only of young spermatids. Water-insoluble T autoantigen was found on the plasmalemma and outer acrosomal membranes of spermatids and spermatozoa, inside the spermatid cytoplasm and, sometimes, on the inner acrosomal membrane of young spermatids. The specificity of the immunological localization for each antigen was confirmed by testing with specific antisera following absorption with homologous and heterologous antigens. No other testicular cell type (including Sertoli cells per se) was found to bear S, P or T autoantigens. When use was made of autoimmune sera obtained through autologous whole spermatozoa, the observed staining was an additive combination of what was observed when using the preceding three immune sera, anti-S, anti-P and anti-T.


1978 ◽  
Vol 32 (1) ◽  
pp. 177-184
Author(s):  
D.P. Green ◽  
A.R. Hockaday

The protease acrosin is widely considered to be an essential component of a zona lysin which enables sperm to penetrate the zona pellucida of the egg. Sperm form a characteristic penetration slit little wider than the sperm head itself and this has long suggested that any zona lysin is attached to the sperm surface after an acrosome reaction. This paper provides the first ultrastructural evidence that this is the case. The protein acrosin inhibitor, Kunitz soybean trypsin inhibitor, has been covalently attached to the electron-dense marker, ferritin, and the conjugate incubated with guinea-pig sperm which have undergone an A23187-induced acrosome reaction. Electron microscopy shows that ferritin is distributed unevenly over the outer surface of the newly exposed inner acrosomal membrane but does not extend to the equatorial segment. This is further evidence that acrosin can be considered as a candidate for the role of zona lysin. The mechanism of sperm penetration of the zona is discussed in the light of these observations.


1979 ◽  
Vol 39 (1) ◽  
pp. 1-12
Author(s):  
M. Berrios ◽  
J.M. Bedford

Primary oocytes cannot be fertilized normally; they begin to develop this capacity as meiosis resumes. To elucidate the changes involved in acquisition of their fertilizability, rabbit primary oocytes displaying a germinal vesicle (GV oocytes) were placed in Fallopian tubes inseminated previously with spermatozoa, recovered 2–5 h later and examined by light and electron microscopy. At least 4 aspects of GV oocyte/sperm interaction were abnormal. Although the vestments and oolemma seem normally receptive to spermatozoa, fusion with the oolemma of the primary oocyte did not elicit exocytosis of cortical granules, and consequently multiple entry of spermatozoa into the ooplasm was common. Secondly, the GV oocyte cortex failed to achieve a normal englufment of the anterior part of the sperm head. It sank into the ooplasm capped by only a small rostral vesicle or left the stable inner acrosomal membrane as a patch in the oolemma. Only rarely then was there significant dispersion of the sperm chromatin, and this remained surrounded by nuclear envelope. The persistence of this envelope constitutes a further aberrant feature, for it disappears immediately in secondary oocytes and was absent in primary oocytes in which germinal vesicle breakdown had occurred. The results are discussed with particular reference to current ideas about male pronucleus formation.


1995 ◽  
Vol 108 (10) ◽  
pp. 3267-3278 ◽  
Author(s):  
J.P. Evans ◽  
R.M. Schultz ◽  
G.S. Kopf

The guinea pig sperm protein, PH-30 (also known as fertilin), is postulated to participate in the interaction between the sperm and egg plasma membranes. The beta subunit of guinea pig PH-30 (gpPH-30 beta) contains a domain with homology to disintegrins, snake venom proteins that bind to integrins via an integrin-binding domain containing the tripeptide RGD. This raises the question of whether an egg integrin serves as a receptor for PH-30. Although mouse eggs express integrin subunits, their role in mouse fertilization is unresolved. Therefore, we examined fertilization for two different hallmarks of integrin function, namely, dependence of ligand binding on divalent cations and the ability to inhibit ligand binding with RGD peptides. We demonstrate that sperm binding to zona pellucida-free eggs is supported by Ca2+, Mg2+, or Mn2+. Ca2+ was necessary and sufficient for sperm-egg fusion, with 2.5 mM Ca2+ being the most effective concentration. In addition, fertilization could be partially inhibited with various RGD peptides, which caused a decrease in sperm-egg fusion by 30–58%. This partial inhibition of fusion with RGD peptides prompted the cloning of the mouse homologue of gpPH-30 beta (hereafter referred to as mPH-30 beta) to determine if it possessed the tripeptide RGD or a different amino acid sequence in its disintegrin domain. mPH-30 beta, which is expressed during meiotic and post-meiotic phases of spermatogenesis, shares significant similarities to gpPH-30 beta throughout the length of the molecule, from the signal sequence to the cytoplasmic tail. The full-length deduced amino acid sequence of mPH-30 beta. The disintegrin domain of mPH-30 beta has the tripeptide QDE (instead of RGD) in its cell recognition region. Peptides containing this QDE sequence decrease the binding and fusion of sperm with zona pellucida-free eggs by approximately 70%, suggesting that the disintegrin domain of mPH-30 beta participates in the interaction between sperm and egg membranes.


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