Articoli di riviste: "Zona pellucida"

1

Rankin, T. L., Z. B. Tong, P. E. Castle, E. Lee, R. Gore-Langton, L. M. Nelson e J. Dean. "Human ZP3 restores fertility in Zp3 null mice without affecting order-specific sperm binding". Development 125, n. 13 (1 luglio 1998): 2415–24. http://dx.doi.org/10.1242/dev.125.13.2415.

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The mammalian zona pellucida surrounding ovulated eggs mediates sperm binding at fertilization, provides a postfertilization block to polyspermy, and facilitates passage of pre-implantation embryos down the oviduct. Although the three zona proteins (ZP1, ZP2, ZP3) are well conserved, mammalian fertilization is relatively specific and human sperm do not bind to the mouse zona pellucida. There are considerable in vitro data that ZP3 acts as a primary sperm adhesion molecule in mice and, by analogy, a similar role has been postulated for human ZP3. Genetically altered mice lacking ZP3 (Zp3(tm/tm)) do not form a zona pellucida and are infertile. To rescue this phenotype, transgenic mice expressing human ZP3 (67% identical to mouse ZP3) were produced and bred with Zp3(tm/tm) null mice. The resultant human ZP3 rescue females had chimeric zonae pellucidae composed of mouse ZP1, mouse ZP2 and human ZP3. Human ZP3 expressed in mouse oocytes had an apparent mass (64 kDa) indistinguishable from native human ZP3 and distinct from mouse ZP3 (83 kDa). Despite the presence of human ZP3, human sperm did not bind to the chimeric zona pellucida, and notwithstanding the absence of mouse ZP3, mouse sperm bound to ovulated eggs in vitro and fertility was restored in vivo. These data have implications regarding the molecular basis of mouse and human sperm binding to their respective zonae pellucidae.

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Cao, Zuowu, Chuncheng Nie, Yan Xie e Dongqin Cai. "The bioactivities of the central segment of Zp2 polypeptide". Zygote 24, n. 5 (19 maggio 2016): 768–74. http://dx.doi.org/10.1017/s0967199416000095.

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SummaryIn order to understand the role of the protein zona pellucida 2 in fertilization, an antibody against a central segment of the zona pellucida 2 peptide, segment 190–505 (Z2eH), was prepared. The influence of the antibody on sperm–zona interaction was tested using the sperm–egg binding assay. The effect of the antibody on fertility was evaluated by passive immunization with anti-Z2eH antibody. Immunohistochemical assay showed that an antibody from rabbit reacted specifically with the natural zona pellucida on mouse ovarian sections. Immunofluorescence assay showed that the antibody bound specifically to the zonae pellucidae of the ovulated oocytes and 2-cell embryos after passive immunization. The antibody-treated oocytes bound capacitated sperm as control oocytes, passive immunization did not impede the action of sperm to fertilize the oocyte in vivo. These findings suggest that the central peptide of ZP2 (190–505) is immunogenic and contains zona pellucida-specific epitopes, however the central polypeptide might not be the crucial part from which to construct a functional domain to bind sperm.

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Lopez, L. C., E. M. Bayna, D. Litoff, N. L. Shaper, J. H. Shaper e B. D. Shur. "Receptor function of mouse sperm surface galactosyltransferase during fertilization." Journal of Cell Biology 101, n. 4 (1 ottobre 1985): 1501–10. http://dx.doi.org/10.1083/jcb.101.4.1501.

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Past studies from this laboratory have suggested that mouse sperm binding to the egg zona pellucida is mediated by a sperm galactosyltransferase (GalTase), which recognizes and binds to terminal N-acetylglucosamine (GlcNAc) residues in the zona pellucida (Shur, B. D., and N. G. Hall, 1982, J. Cell Biol. 95:567-573; 95:574-579). We now present evidence that directly supports this mechanism for gamete binding. GalTase was purified to homogeneity by sequential affinity-chromatography on GlcNAc-agarose and alpha-lactalbumin-agarose columns. The purified enzyme produced a dose-dependent inhibition of sperm binding to the zona pellucida, relative to controls. To inhibit sperm/zona binding, GalTase had to retain its native conformation, since neither heat-inactivated nor Mn++-deficient GalTase inhibited sperm binding. GalTase inhibition of sperm/zona binding was not due to steric blocking of an adjacent sperm receptor on the zona, since GalTase could be released from the zona pellucida by forced galactosylation with UDPGal, and the resulting galactosylated zona was still incapable of binding sperm. In control experiments, when UDPGal was replaced with the inappropriate sugar nucleotide, UDPglucose, sperm binding to the zona pellucida remained normal after the adsorbed GalTase was washed away. The addition of UDPGal produced a dose-dependent inhibition of sperm/zona binding, and also dissociated preformed sperm/zona adhesions by catalyzing the release of the sperm GalTase from its GlcNAc substrate in the zona pellucida. Under identical conditions, UDP-glucose had no effect on sperm binding to the zona pellucida. The ability of UDPGal to dissociate sperm/zona adhesions was both time- and temperature-dependent. UDPGal produced nearly total inhibition of sperm/zona binding when the zonae pellucidae were first galactosylated to reduce the number of GalTase binding sites. Finally, monospecific anti-GalTase IgG and its Fab fragments produced a dose-dependent inhibition of sperm/zona binding and concomitantly blocked sperm GalTase catalytic activity. Preimmune IgG or anti-mouse brain IgG, which also binds to the sperm surface, had no effect. The sperm GalTase was localized by indirect immunofluorescence to a discrete plasma membrane domain on the dorsal surface of the anterior head overlying the intact acrosome. These results, along with earlier studies, show clearly that sperm GalTase serves as a principal gamete receptor during fertilization.

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Baibakov, Boris, Nathan A. Boggs, Belinda Yauger, Galina Baibakov e Jurrien Dean. "Human sperm bind to the N-terminal domain of ZP2 in humanized zonae pellucidae in transgenic mice". Journal of Cell Biology 197, n. 7 (25 giugno 2012): 897–905. http://dx.doi.org/10.1083/jcb.201203062.

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Fertilization requires taxon-specific gamete recognition, and human sperm do not bind to zonae pellucidae (ZP1–3) surrounding mouse eggs. Using transgenesis to replace endogenous mouse proteins with human homologues, gain-of-function sperm-binding assays were established to evaluate human gamete recognition. Human sperm bound only to zonae pellucidae containing human ZP2, either alone or coexpressed with other human zona proteins. Binding to the humanized matrix was a dominant effect that resulted in human sperm penetration of the zona pellucida and accumulation in the perivitelline space, where they were unable to fuse with mouse eggs. Using recombinant peptides, the site of gamete recognition was located to a defined domain in the N terminus of ZP2. These results provide experimental evidence for the role of ZP2 in mediating sperm binding to the zona pellucida and support a model in which human sperm–egg recognition is dependent on an N-terminal domain of ZP2, which is degraded after fertilization to provide a definitive block to polyspermy.

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5

Brown, C. R., e W. K. T. Cheng. "Changes in composition of the porcine zona pellucida during development of the oocyte to the 2- to 4-cell embryo". Development 92, n. 1 (1 marzo 1986): 183–91. http://dx.doi.org/10.1242/dev.92.1.183.

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Our objective was to identify any changes that occur in the composition of the porcine zona pellucida during development of the 2- to 4-cell embryo from the oocyte. Oocytes, unfertilized eggs and single and 2- to 4-cell embryos have been recovered surgically and their zonae pellucidae 125I-labelled and analysed individually by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The zonae from ovulated eggs possessed two major glycoproteins Mr 250000 and 90000 which were absent from follicular oocytes but present in the fluid from the oestrus, but not luteal, oviduct. The glycoproteins remained on the zona pellucida of 2- to 4-cell embryos whose analysis showed the presence of additional polypeptides of Mr 150000, 57000, 50000 and 25000. It is concluded (i) that shortly after ovulation, and in spite of the presence around the egg of cumulus oophorus and corona radiata cells, significant amounts of oviducal glycoproteins are able to bind firmly to the zona pellucida, and (ii) that after contact with spermatozoa there is evidence of a limited hydrolysis of the structure by the sperm protease acrosin.

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6

Moreno, R. D., M. S. Sepúlveda, A. de Ioannes e C. Barros. "The polysulphate binding domain of human proacrosin/acrosin is involved in both the enzyme activation and spermatozoa-zona pellucida interaction". Zygote 6, n. 1 (febbraio 1998): 75–83. http://dx.doi.org/10.1017/s0967199400005104.

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SummaryMammalian acrosin is a protease present as a zymogen in the acrosome of a non-reacted mammalian sperm, and in vitro is able to carry out limited hydrolysis of homologous and heterologous zonae pellucidae. On the other hand, sulphated polymers and zona pellcida glycoproteins bind to acrosin on a domain different from the active site, named the polysulphate binding domain (PSBD). Thus it is believed that acrosome-reacted spermatozoa bind to glycan chains of the zona pellucida through PSBD participating as secondary binding receptor. The aim of the present work was to study the role of PSBD during both human gamete interaction and acrosin activation. In this work we present evidence that the anti-human acrosin monoclonal antibody C5F10 is directed to an epitope located on or near the PSBD on human proacrosin/acrosin. Moreover, we show that this antibody is able to inhibit both proacrosin activation induced by fucoidan and the sperm binding to the zona pellucida. Our results suggest that the same PSBD is involved in both sperm secondary binding, during zona pellucida penetration, and proacrosin activation.

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7

Mertens, E., U. Besenfelder, M. Gilles, M. Hölker, F. Rings, V. Havlicek, K. Schellander e A. Herrler. "190 INFLUENCE OF IN VITRO CULTURE OF BOVINE EMBRYOS ON THE STRUCTURE OF THE ZONA PELLUCIDA". Reproduction, Fertility and Development 19, n. 1 (2007): 211. http://dx.doi.org/10.1071/rdv19n1ab190.

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The zona pellucida is an extracellular structure at the direct interface between the maternal and embryonic sides, through which all signals of the embryo–maternal dialogue as well as nutritional factors have to pass. Up to now there has been no investigation as to whether in vitro culture influences the structure of the zona pellucida compared to that of in vivo embryos. Therefore, in vitro (oocyte, zygote, 2-, 4-, 8-, 16-cell, morula, and Day 7 blastocyst, using the protocol published by Nganvongpanit et al. 2006 Reproduction 131, 861–874) and in vivo (zygote, 4-cell, morula, and blastocyst) embryos were prepared for microscopical investigation. In total, 191 in vitro and 99 in vivo embryos of quality 1 and 2 from at least 2 replicates were used. Araldit-embedded embryos were semi-thin-sectioned and stained with hematoxilin. A morphometrical evaluation was performed to determine the percentage of the more reticular outer part compared to the total thickness of the zona. Furthermore, the total thickness of the zona pellucida was compared between in vitro and in vivo embryos. In parallel, embryos were analyzed by scanning electron microscopy. Up to the 16-cell stage, the zona of in vivo and in vitro embryos is similar, but in vivo morulae and blastocysts show significantly thicker zonae than the in vitro stages. The reticular part of the zona is thicker in in vivo embryos than in in vitro embryos (30.2 � 2.1% vs. 12.4 � 1.8%, respectively). Investigating the pores of the zona pellucida, in vivo morulae/blastocysts show smaller-sized pores than in those derived in vitro. Most of the in vivo morulae/blastocysts are totally covered by secreted granules, and therefore the pores could not be investigated. Furthermore, 30-50% of the in vitro embryos show partly degenerated outer layers of the zona pellucida. This investigation demonstrates that in vitro and in vivo zonae pellucidae are significantly different, reflecting a negative influence of the IVM and IVC.

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8

Wassarman, Paul M. "Zona Pellucida Glycoproteins". Annual Review of Biochemistry 57, n. 1 (giugno 1988): 415–42. http://dx.doi.org/10.1146/annurev.bi.57.070188.002215.

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9

Wassarman, Paul M. "Zona Pellucida Glycoproteins". Journal of Biological Chemistry 283, n. 36 (6 giugno 2008): 24285–89. http://dx.doi.org/10.1074/jbc.r800027200.

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10

Avella, Matteo A., Boris Baibakov e Jurrien Dean. "A single domain of the ZP2 zona pellucida protein mediates gamete recognition in mice and humans". Journal of Cell Biology 205, n. 6 (16 giugno 2014): 801–9. http://dx.doi.org/10.1083/jcb.201404025.

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The extracellular zona pellucida surrounds ovulated eggs and mediates gamete recognition that is essential for mammalian fertilization. Zonae matrices contain three (mouse) or four (human) glycoproteins (ZP1–4), but which protein binds sperm remains controversial. A defining characteristic of an essential zona ligand is sterility after genetic ablation. We have established transgenic mice expressing human ZP4 that form zonae pellucidae in the absence of mouse or human ZP2. Neither mouse nor human sperm bound to these ovulated eggs, and these female mice were sterile after in vivo insemination or natural mating. The same phenotype was observed with truncated ZP2 that lacks a restricted domain within ZP251–149. Chimeric human/mouse ZP2 isoforms expressed in transgenic mice and recombinant peptide bead assays confirmed that this region accounts for the taxon specificity observed in human–mouse gamete recognition. These observations in transgenic mice document that the ZP251–149 sperm-binding domain is necessary for human and mouse gamete recognition and penetration through the zona pellucida.

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Hoodbhoy, Tanya, e Jurrien Dean. "Insights into the molecular basis of sperm–egg recognition in mammals". Reproduction 127, n. 4 (aprile 2004): 417–22. http://dx.doi.org/10.1530/rep.1.00181.

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The zona pellucida surrounding the egg and pre-implantation embryo is required for in vivo fertility and early development. Explanatory models of sperm–egg recognition need to take into account the ability of sperm to bind to ovulated eggs, but not to two-cell embryos. For the last two decades, investigators have sought to identify an individual protein or carbohydrate side chain as the ‘sperm receptor’. However, recent genetic data in mice are more consistent with the three-dimensional structure of the zona pellucida, rather than a single protein (or carbohydrate), determining sperm binding. The mouse and human zonae pellucidae contain three glycoproteins (ZP1, ZP2, ZP3) and, following fertilization, ZP2 is proteolytically cleaved. The replacement of endogenous mouse proteins with human ZP2, ZP3 or both does not alter taxon specificity of sperm binding or prevent fertility. Surprisingly, human ZP2 is not cleaved following fertilization and intact ZP2 correlates with persistent sperm binding to two-cell embryos. Taken together, these data support a model in which the cleavage status of ZP2 modulates the three-dimensional structure of the zona pellucida and determines whether sperm bind (uncleaved) or do not (cleaved).

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12

Gadella, B. M. "002. PIG SPERM EGG INTERACTION AND FORMATION OF A ZONA PELLUCIDA BINDING COMPLEX". Reproduction, Fertility and Development 22, n. 9 (2010): 2. http://dx.doi.org/10.1071/srb10abs002.

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In order to achieve fertilization sperm cells first need to successfully interact with the zona pellucida. Before reaching the zona pellucida the sperm cell undergoes extensive remodeling both in the male and female genital tract. These changes serve to mediate optimal recognition of the zona pellucida in the oviduct (primary zona pellucida binding). Optimal sperm-zona interactions are crucial for porcine oocyte fertilization: The zona pellucida- attached sperm cell is triggered to undergo the acrosome reaction and will also become hypermotile. Together these two responses allow the sperm cell to drill through the zona pellucida (secondary zona pellucida binding) this coincides with local sperm zona drilling so that a few sperm can reach the perivitellin space. This delaying strategy allows only one sperm cell in a given time-point to bind and fuse with the oocyte (fertilization) and thus minimizes the risk of polyspermy. The polyspermy block is essentially executed by the fertilized oocyte that immediately secretes its cortical granule content into the perivitellin space. This content blocks sperm-oocyte fusion either by sticking to the oolemma or by the induction of a biochemical reaction of the zona pellucida (zona pellucida hardening). The cortical reaction thus blocks sperm-zona pellucida binding and/or sperm-zona pellucida drilling. Note that zona pellcuida interactions under pig IVF conditions relatively frequently result in polyspermy. It is not clear whether this is also the case in vivo after natural mating. More importantly we do not know how other artificial reproductive technologies affect polyspermy rates. This is especially relevant for new sperm treatments and insemination technologies in which sperm are activated by capacitation media essentially mimicking the IVF media. Therefore, better understanding of sperm activation and of the arrangement of proteins involved in zona pellucida interactions are relevant for designing strategies to further improve pig reproduction.

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Hasegawa, Akiko, Nozomi Kanazawa, Hideaki Sawai, Shinji Komori e Koji Koyama. "Pig zona pellucida 2 (pZP2) protein does not participate in zona pellucida formation in transgenic mice". Reproduction 132, n. 3 (settembre 2006): 455–64. http://dx.doi.org/10.1530/rep.1.01016.

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The zona pellucida, an extracellular matrix surrounding mammalian oocytes, is composed of three or four glycoproteins. It is well known that the zona pellucida plays several critical roles during fertilization, but there is little knowledge about its formation. The purpose of this study is to examine whether a pig zona pellucida glycoprotein 2 (pZP2) would assemble with mouse zona pellucida. A transgene construct was prepared by placing a minigene encoding pZP2 downstream from the promoter of mouse ZP2. The result showed that the transgenic protein was synthesized in growing oocytes but not incorporated into the zona pellucida. Furthermore, the pZP2 transgene did not rescue the phenotype in ZP2-knockout zona-deficient mice. These results indicate that pZP2 does not participate in mouse zona pellucida formation and the zona pellucida is constituted from its component proteins in a molecular species-specific manner between mice and pigs.

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Zhao, Ming, Lyn Gold, Heidi Dorward, Li-fang Liang, Tanya Hoodbhoy, Emily Boja, Henry M. Fales e Jurrien Dean. "Mutation of a Conserved Hydrophobic Patch PreventsIncorporation of ZP3 into the Zona Pellucida SurroundingMouseEggs". Molecular and Cellular Biology 23, n. 24 (15 dicembre 2003): 8982–91. http://dx.doi.org/10.1128/mcb.23.24.8982-8991.2003.

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ABSTRACT Three glycoproteins (ZP1, ZP2, and ZP3) are synthesized in growing mouse oocytes and secreted to form an extracellular zona pellucida that mediates sperm binding and fertilization. Each has a signal peptide to direct it into a secretory pathway, a “zona” domain implicated in matrix polymerization and a transmembrane domain from which the ectodomain must be released. Using confocal microscopy and enhanced green fluorescent protein (EGFP), the intracellular trafficking of ZP3 was observed in growing mouse oocytes. Replacement of the zona domain with EGFP did not prevent secretion of ZP3, suggesting the presence of trafficking signals and a cleavage site in the carboxyl terminus. Analysis of linker-scanning mutations of a ZP3-EGFP fusion protein in transient assays and in transgenic mice identified an eight-amino-acid hydrophobic region required for secretion and incorporation into the zona pellucida. The hydrophobic patch is conserved among mouse zona proteins and lies between a potential proprotein convertase (furin) cleavage site and the transmembrane domain. The cleavage site that releases the ectodomain from the transmembrane domain was defined by mass spectrometry of native zonae pellucidae and lies N-terminal to a proprotein convertase site that is distinct from the hydrophobic patch.

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Jovine, Luca, Costel C. Darie, Eveline S. Litscher e Paul M. Wassarman. "ZONA PELLUCIDA DOMAIN PROTEINS". Annual Review of Biochemistry 74, n. 1 (giugno 2005): 83–114. http://dx.doi.org/10.1146/annurev.biochem.74.082803.133039.

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Nagy, A. "Removal of Zona Pellucida". Cold Spring Harbor Protocols 2006, n. 21 (1 agosto 2006): pdb.prot4421. http://dx.doi.org/10.1101/pdb.prot4421.

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Saxena, D. K., I. Tanii, T. Oh-oka, K. Yoshinaga e K. Toshimori. "Behaviour and role of an intra-acrosomal antigenic molecule, acrin 3, during mouse fertilisation in vitro". Zygote 8, n. 4 (novembre 2000): 329–38. http://dx.doi.org/10.1017/s096719940000112x.

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In this study we examined the behaviour and role of an intra-acrosomal antigenic molecule, acrin 3, during mouse fertilisation in vitro by assessing the effect of its pertinent monoclonal antibody mMC101. Experiments were designed to assess the effect of mMC101 on sperm–zona pellucida binding, the acrosome reaction, zona pellucida penetration, sperm–egg fusion, and fertilisation in vitro. mMC101 did not affect sperm motility or primary and secondary binding to the zona pellucida, but significantly inhibited fertilisation of zona-pellucida-intact oocytes in a dose-dependent manner. In the presence of mMC101 at 100 μg/ml concentration in TYH medium, none of the oocytes developed to pronuclear stage by 5 h after co-incubation of the gametes, but the pronucleus formation rate recovered to some extent (45.3%) after 8 h, indicating a delay of early embryonic development. mMC101 also delayed and significantly suppressed zona pellucida penetration by sperm. Acrin 3 dispersed and did not remain on completely acrosome-reacted sperm. Although mMC101 did not influence the zona-pellucida-induced acrosome reaction, it significantly inhibited fertilisation when acrosome-reacted sperm in the presence of mMC101 inseminated zona-pellucida-free oocytes. However, fertilisation remained unaffected when acrosome-reacted sperm in the absence of mMC101 inseminated zona-pellucida-free oocytes even in its presence. Thus, acrin 3 appears to facilitate zona pellucida penetration and is also likely to be involved in sperm–oocyte fusion by modifying the sperm plasma membrane during the acrosome reaction.

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Kitchener, A. L., L. M. Edds, F. C. Molinia e D. J. Kay. "Porcine zonae pellucidae immunisation of tammar wallabies (Macropus eugenii): fertility and immune responses". Reproduction, Fertility and Development 14, n. 4 (2002): 215. http://dx.doi.org/10.1071/rd01121.

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This study looked at the feasibility of targeting the zona pellucida for a contraceptive vaccine as a possible alternative method of control for overabundant macropods. Tammar wallabies, as a model for other macropods, were immunized with porcine zonae pellucidae (PZP) and were found to achieve significant concentrations of antibody to PZP in sera and reproductive tract fluids. Wallabies immunized with PZP exhibited lower ovarian weight with reduced numbers of antral follicles when compared with control animals. Wallabies were placed in a natural mating trial followed by an artificial insemination trial. None of the PZP-immunized wallabies produced offspring in the natural mating trial compared with 67% of control animals. To further assess fertility, a sub-sample of the wallabies were superovulated and artificially inseminated. This resulted in all control wallabies producing fertilized ova and all PZP-immunized wallabies failing to ovulate. These results suggest that immunocontraception based on targeting antigens of the zona pellucida may be an effective strategy for fertility reduction in macropods.

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Kinloch, R. A., S. Mortillo e P. M. Wassarman. "Transgenic mouse eggs with functional hamster sperm receptors in their zona pellucida". Development 115, n. 4 (1 agosto 1992): 937–46. http://dx.doi.org/10.1242/dev.115.4.937.

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Sperm receptors are located in the mammalian egg extracellular coat, or zona pellucida. Mouse and hamster sperm receptor glycoproteins, mZP3 (83 × 10(3) M(r)) and hZP3 (56 × 10(3) M(r)), respectively, have very similar polypeptides (44 × 10(3) M(r); 81% identical) that are glycosylated to different extents. Purified mZP3 and hZP3 can bind to mouse sperm, prevent them from binding to eggs and induce them to undergo exocytosis, the acrosome reaction, in vitro. A DNA construct that placed the hZP3 gene under the control of mZP3 gene 5′-flanking sequence was used in this report to produce two mouse lines that harbored the foreign sperm receptor transgene. In both lines, the transgene was expressed only by growing oocytes, at a level comparable to that of the endogenous mZP3 gene, and the developmental pattern of transgene expression resembled that of the mZP3 gene. In addition to mZP3, transgenic mouse oocytes synthesized and secreted a glycoprotein indistinguishable from hZP3, and incorporated both glycoproteins into a mosaic zona pellucida. Importantly, hZP3 purified from such zonae pellucidae exhibited both sperm receptor and acrosome reaction-inducing activities in vitro and, following fertilization of transgenic mouse eggs, was inactivated. These results demonstrate that a biologically active foreign sperm receptor can be synthesized and secreted by transgenic mouse oocytes, assembled into a mosaic zona pellucida, and inactivated following fertilization as part of the secondary block to polyspermy.

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Hoodbhoy, Tanya, Manuel Avilés, Boris Baibakov, Olga Epifano, María Jiménez-Movilla, Lyn Gauthier e Jurrien Dean. "ZP2 and ZP3 Traffic Independently within Oocytes prior to Assembly into the Extracellular Zona Pellucida". Molecular and Cellular Biology 26, n. 21 (1 novembre 2006): 7991–98. http://dx.doi.org/10.1128/mcb.00904-06.

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ABSTRACT The extracellular zona pellucida surrounds mammalian eggs and mediates taxon-specific sperm-egg recognition at fertilization. In mice, the zona pellucida is composed of three glycoproteins, but the presence of ZP2 and ZP3 is sufficient to form a biologically functional structure. Each zona pellucida glycoprotein is synthesized in growing oocytes and traffics through the endomembrane system to the cell surface, where it is released from a transmembrane domain and assembled into the insoluble zona pellucida matrix. ZP2 and ZP3 colocalize in the endoplasmic reticulum and in 1- to 5-μm post-Golgi structures comprising multivesicular aggregates (MVA), but a coimmunoprecipitation assay does not detect physical interactions. In addition, ZP2 traffics normally in growing oocytes in the absence of ZP3 or if ZP3 has been mutated to prevent incorporation into the zona pellucida matrix, complementing earlier studies indicating the independence of ZP3 secretion in Zp2 null mice. N glycosylation has been implicated in correct protein folding and intracellular trafficking of secreted proteins. Although ZP3 contain five N-glycans, enhanced green fluorescent protein-tagged ZP3 lacking N glycosylation sites is present in MVA and is incorporated into the zona pellucida matrix of transgenic mice. Thus, ZP2 secretion is seemingly unaffected by ZP3 lacking N-glycans. Taken together, these observations indicate that ZP2 and ZP3 traffic independently through the oocyte prior to assembly into the zona pellucida.

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21

Rogers, K. D., B. A. Foster, E. J. Guiterrez, F. A. Diaz e K. R. Bondioli. "41 Effects of Dimethyl Sulfoxide- or Glycerol-Based Vitrification Protocols on Zona Pellucida Hardening in Mature Bovine Oocytes". Reproduction, Fertility and Development 30, n. 1 (2018): 160. http://dx.doi.org/10.1071/rdv30n1ab41.

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Zona pellucida hardening is a natural process that occurs after oocyte fertilization to prevent polyspermic fertilization and to protect embryonic development. Pre-fertilization hardening of the zona pellucida, however, decreases fertilization rates. Cryoprotectants have also been shown to negatively affect fertilization rates, one possible mechanism of which being through zona hardening. This experiment was conducted to determine the effect of different cryoprotectants on hardening of the zona pellucida of mature bovine oocytes. Oocytes were collected by ovum pick-up (OPU) by transvaginal ultrasound guided aspiration (TUGA) from mixed-breed cows. After collection, oocytes were randomly assigned to 3 cryoprotectant treatment groups: dimethyl sulfoxide (DMSO), glycerol, or PBS (control). Drops (50 µL) of each vitrification solution were placed under mineral oil. Vitrification solution 1 (VS1) contained 10% ethylene glycol (EG), either 10% DMSO or glycerol, and 0.5 M sucrose. Vitrification solution 2 (VS2) contained 20% EG, 20% DMSO or glycerol, and 0.5 M sucrose. All oocytes were held in VS1 for 5 min before being transferred to VS2 for 45 s. All oocytes were washed in a common dilution solution (80% PBS, 20% calf serum, 0.025 M sucrose) for 5 min. Next, oocytes were moved to 50-µL drops of protease solution (0.1% protease) under mineral oil. Control oocytes were held in PBS for ~10 min before entering the protease solution to represent the same period as the vitrification procedure. The oocytes were observed until the zonae pellucidae were completely digested and times were recorded for each oocyte. This experiment included 4 replicates with a total of 88 oocytes used, 32 each in DMSO and glycerol and 24 in PBS. The data were analysed using ANOVA. The DMSO group had the lower mean zona digestion time out of the 2 cryoprotectants at 15.75 min and glycerol had the highest mean digestion time at 19.3 min. The control group (PBS) had the lowest mean of the 3 treatments at 12.7 min. The differences between DMSO and glycerol, and between DMSO and PBS were not significant (P = 0.0654 and 0.1073, respectively). However, both glycerol versus PBS and the average of DMSO and glycerol versus PBS were significantly different (P-value = 0.0053 and 0.0119, respectively). These results suggest that glycerol hardens the zona pellucida more than DMSO or PBS; however, there is not enough evidence to determine whether DMSO hardens the zona pellucida compared with PBS. This would suggest that, in relation to zona hardening and ensuring proper fertilization, glycerol-based cryoprotectants may be a better option than DMSO-based ones. Further, these results may be important in embryo vitrification as zona hardening may prevent blastocyst hatching, suggesting that glycerol-based cryoprotectants should be investigated as the optimal cryoprotectant here also.

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22

Ganeva, Rumiana, Dimitar Parvanov, Denitsa Velikova, Magdalena Vasileva, Kristina Nikolova e Georgi Stamenov. "Sperm morphology and DNA fragmentation after zona pellucida selection". Reproduction and Fertility 2, n. 3 (15 settembre 2021): 221–30. http://dx.doi.org/10.1530/raf-21-0041.

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Abstract (sommario):

Sperm DNA fragmentation (SDF) and sperm morphological defects can negatively affect ART outcomes. Consequently, there is a need for additional semen processing technique that accounts for sperm DNA status and morphology prior to ICSI. The objective was to evaluate the efficacy of an additional zona pellucida adhesion-based sperm selection for obtaining sperm populations with a high percentage of normal morphology and DNA integrity as compared to native semen and routine swim-up preparation. Semen samples from 78 normozoospermic men were subjected to swim up and placed in petri dishes coated with 48 acid-solubilized zonae pellucidae. Sperm DNA fragmentation and morphology were assessed in the native semen, the swim-up samples, and the zona-adhered spermatozoa from each patient. The mean sperm DNA fragmentation of the zona-selected spermatozoa (3.5 ± 0.7%) was significantly lower than the swim-up samples (15.3 ± 5.2%) (P < 0.001) and native semen (24.9 ± 7.1%) (P < 0.001). All of the samples had lower levels of DNA damage after additional selection by zona pellucida adhesion. Significantly higher percentage of sperm with normal morphology was observed after zona-adhesion selection (11.4 ± 3.9%) when compared to the swim-up samples (8.9 ± 4.3%) (P < 0.001) or the native semen (5.3 ± 3.2%) (P < 0.001). In 94% of the samples, the percentage of spermatozoa with normal morphology increased after the additional zona selection. This study demonstrates that sperm selection by additional zona-adhesion technique yields a significantly higher percentage of spermatozoa with normal morphology as well as a significantly decreased level of DNA fragmentation when compared to the native semen and the swim-up-only prepared samples. Lay summary High level of DNA folding known as sperm DNA fragmentation (SDF) inside each sperm and defects in the shape, size, and structure of the sperm can negatively affect assisted reproduction treatment (ART) outcomes. Consequently, there is a need for additional semen processing techniques that account for sperm quality prior to ART. Our team designed a simple technique using proteins from the coat around the egg (zona pellucida) to enhance sperm selection procedures based on natural sperm–egg interactions. Using this technique in combination with the most common techniques used in ART yields a significantly higher percentage of sperm with normal shape, size, and structure and a decreased level of DNA fragmentation. This sperm zona-selection technique would be beneficial if introduced in the ART practice to yield sperm with higher fertilization potential.

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23

Paterson, Margaret, Zoë A. Jennings, Marcel van Duin e R. John Aitken. "Immunocontraception with Zona pellucida Proteins". Cells Tissues Organs 166, n. 2 (2000): 228–32. http://dx.doi.org/10.1159/000016735.

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24

Zhao, Ming, Lyn Gold, Ann M. Ginsberg, Li-Fang Liang e Jurrien Dean. "Conserved Furin Cleavage Site Not Essential for Secretion and Integration of ZP3 into the Extracellular Egg Coat of Transgenic Mice". Molecular and Cellular Biology 22, n. 9 (1 maggio 2002): 3111–20. http://dx.doi.org/10.1128/mcb.22.9.3111-3120.2002.

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Abstract (sommario):

ABSTRACT The extracellular zona pellucida surrounding mammalian eggs is formed by interactions of the ZP1, ZP2, and ZP3 glycoproteins. Female mice lacking ZP2 or ZP3 do not form a stable zona matrix and are sterile. The three zona proteins are synthesized in growing oocytes and secreted prior to incorporation into the zona pellucida. A well-conserved furin site upstream of a transmembrane domain near the carboxyl terminus of each has been implicated in the release of the zona ectodomains from oocytes. However, mutation of the furin site (RNRR → ANAA) does not affect the intracellular trafficking or secretion of an enhanced green fluorescent protein (EGFP)-ZP3 fusion protein in heterologous somatic cells. After transient expression in growing oocytes, normal EGFP-ZP3 and mutant EGFP-ZP3 associate with the inner aspect of the zona pellucida, which is distinct from the plasma membrane. These in vitro results are confirmed in transgenic mice expressing EGFP-ZP3 with or without the mutant furin site. In each case, EGFP-ZP3 is incorporated throughout the width of the zona pellucida and the transgenic mice are fertile. These results indicate that the zona matrix accrues from the inside out and, unexpectedly, suggest that cleavage at the furin site is not required for formation of the extracellular zona pellucida surrounding mouse eggs.

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25

Yurchuk, Taisiia A., Maryna P. Petrushko, Volodymyr I. Piniaiev e Natalya A. Buderatska. "Vitrification of Human Embryos After Manipulation with Zona Pellucida". Problems of Cryobiology and Cryomedicine 28, n. 2 (25 giugno 2018): 184. http://dx.doi.org/10.15407/cryo28.02.184.

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26

Kan, F. W., S. St-Jacques e G. Bleau. "Immunoelectron microscopic localization of an oviductal antigen in hamster zona pellucida by use of a monoclonal antibody." Journal of Histochemistry & Cytochemistry 36, n. 11 (novembre 1988): 1441–47. http://dx.doi.org/10.1177/36.11.3171167.

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Abstract (sommario):

The zona pellucida is an extracellular matrix of glycoproteins which surrounds the mammalian oocyte and preimplantation embryo. We have recently developed monoclonal antibodies against oviductal zona pellucida of the golden hamster. We applied the post-embedding immunocytochemical method using a monoclonal antibody (IgGl,k) to determine the precise location of antigenic sites in the cumulus oophorus complex of the superovulated hamster. By applying the high-resolution protein A-gold technique, we demonstrated that the sites of immunoreactivity were exclusively in the zona pellucida encompassing the oocyte. Other structures within the oocyte and neighboring cumulus cells were not labeled by gold particles. Moreover, gold particles were evenly distributed throughout the entire thickness of the zona pellucida, indicating that this extracellular layer is at least in part made up of an antigen recognized by the monoclonal antibody that is uniformly distributed in the zona matrix.

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27

Urch, U. A., e H. Patel. "The interaction of boar sperm proacrosin with its natural substrate, the zona pellucida, and with polysulfated polysaccharides". Development 111, n. 4 (1 aprile 1991): 1165–72. http://dx.doi.org/10.1242/dev.111.4.1165.

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Abstract (sommario):

Boar sperm acrosin is an acrosomal protease with trypsin-like specificity, and it functions in fertilization by assisting sperm passage through the zona pellucida by limited hydrolysis of this extracellular matrix. In addition to a proteolytic active site domain, acrosin binds the zona pellucida at a separate binding domain that is lost during proacrosin autolysis. In this study, we quantitate the binding of proacrosin to the physiological substrate for acrosin, the zona pellucida, and to a non-substrate, the polysulfated polysaccharide fucoidan. Binding was analogous to sea urchin sperm bindin that binds egg jelly fucan and the vitelline envelope of sea urchin eggs. Proacrosin was found to bind to fucoidan and to the zona pellucida with binding affinities similar to bindin interaction with egg jelly fucan. These interactions were competitively inhibited by similar relative molecular mass polysulfated polymers. Since bindin and proacrosin have distinctly different amino acid sequences, their interaction with acidic sulfate esters demonstrates an example of convergent evolution wherein different macromolecules localized in analogous sperm compartments have the same biological function. From cDNA sequence analysis of proacrosin, this binding may be mediated through a consensus sequence for binding sulfated glycoconjugates. Proacrosin binding to the zona pellucida may serve as both a recognition or primary sperm receptor, as well as maintaining the sperm on the zona pellucida once the acrosome reaction has occurred.

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28

Dun, M. D., R. Aitken e B. Nixon. "178. THE CHAPERONIN CONTAINING TCP-1 (CCT/TRiC) MULTISUBUNIT COMPLEX IS INVOLVED IN MEDIATING SPERM - OOCYTE INTERACTIONS". Reproduction, Fertility and Development 22, n. 9 (2010): 96. http://dx.doi.org/10.1071/srb10abs178.

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Abstract (sommario):

Mammalian spermatozoa only express their capacity for fertilization following capacitation, a process characterized by a suite of biophysical and biochemical changes that occurs as the cells ascend the female reproductive tract. A key event associated with the attainment of a capacitated state is a dramatic reorganization of the sperm surface architecture to render these cells competent to bind to the protective matrix of the oocyte, the zona pellucida. Our previous analysis of these remodeling events has provided compelling evidence that they include the assembly and/or presentation of multimeric protein complexes on the sperm surface. In addition, we have demonstrated that at least two of these complexes possess strong affinity for solubilized zona pellucida. In our current study we have utilised mass spectrometry analysis to reveal that one of these complexes comprises the eight subunits that form a composite, multimeric structure known as the chaperonin containing TCP-1 (CCT/TRiC) complex. Our collective data suggest that this complex participates indirectly in zona pellucida interaction, possibly through the conveyance of key zona adhesion molecules to the sperm surface during capacitation. Consistent with this notion, we were able to demonstrate that the sperm CCT/TRiC complex releases its bound substrates upon exposure to ATP, and this treatment induced a significant, concomitant reduction in the ability of capacitated sperm to bind to the zona pellucida. Furthermore, the use of immunoprecipitation assays confirmed the interaction of the CCT/TRiC complex with at least one putative zona pellucida receptor candidate, namely zona pellucida binding protein 2 (ZPBP2). Future work is now aimed at identifying additional zona receptors that may reside within this complex and the pathways that regulate its functional assembly.

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29

Ueno, S., M. Kurome, R. Tomii, K. Hiruma, N. Maeda, H. Saito e H. Nagashima. "185 EMBRYONIC LOSS IN PIGS ASSOCIATED WITH OVIDUCT TRANSPLANTATION OF EARLY-STAGE EMBRYOS WITH DAMAGES IN THE ZONA PELLUCIDA". Reproduction, Fertility and Development 18, n. 2 (2006): 200. http://dx.doi.org/10.1071/rdv18n2ab185.

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Abstract (sommario):

It is assumed that if porcine early-stage embryos with damages in their zonae pellucidae are transplanted to the recipient's oviduct, they may suffer from mechanical and immunological stresses by oviduct contraction and the recipient's immune response. This study aimed to examine the impact of zona pellucida damages, which might arise during nuclear transfer and intra cytoplasmic sperm injection (ICSI), on the development and survival of transplanted embryos. Cumulus-oocyte complexes were collected from ovaries obtained at a local slaughterhouse and matured in vitro in NCSU23 to prepare MII-stage oocytes. The zonae pellucidae of these oocytes were either penetrated with 8- to 10-�m square-ended microinjection pipettes or incised with 35- to 40-�m beveled enucleation pipettes. Intact oocytes were used as controls. The oocytes were electroactivated to induce parthenogenesis and transplanted to the oviducts of estrus-synchronized recipient gilts (estrus-synchronized with 1000 IU eCG and 1500 IU hCG). After 5 to 7 days, the recipient uteri were flushed with PBS supplemented with 1% fetal bovine serum (FBS) to collect embryos, and their development (morula-blastocyst stage embryos/collected embryos) and survival (viable embryos/collected embryos) were determined. In total, 221 zona-penetrated, 129 zona-incised, and 57 intact embryos were transplanted to four, two and two gilts, respectively. The efficiency of embryo recovery was similar in all groups (59.0 to 81.8%). However, the zona-penetrated and zona-incised embryos showed inconsistent development and survival compared with controls; the development and survival rate were 92.6% (25/27) to 96.7% (29/30) and 77.8% (21/27) to 96.7% (29/30) in control embryos, respectively, whereas those of zona-penetrated embryos were 57.1% (28/49) to 95.7% (22/23) and 8.2% (4/49) to 78.3% (18/30), and those of zona-incised embryos were 47.6% (30/63) to 92.3% (36/39) and 23.8% (15/63) to 92.3% (22/23), respectively. Large foci of cells that appeared to be macrophage giant cells were observed at the surface or inside of the degenerated zona-damaged embryos. These results indicate that the recipient's immune response may impair development after transplantation of the embryo to the oviduct, when there is damage in the zona pellucida. This may be one of the factors attributable to the reduced efficiency of live progeny production by ICSI and nuclear transfer. This work was supported by PROBRAIN.

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Schmitz, Carlo, Seyedeh Zeynab Sadr, Hagen Körschgen, Michael Kuske, Jennifer Schoen, Walter Stöcker, Willi Jahnen-Dechent e Julia Floehr. "The E-modulus of the oocyte is a non-destructive measure of zona pellucida hardening". Reproduction 162, n. 4 (1 ottobre 2021): 259–66. http://dx.doi.org/10.1530/rep-21-0122.

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Abstract (sommario):

After fertilization, the oocyte-specific metalloproteinase ovastacin is released and cleaves the zona pellucida protein 2 (ZP2), making the zona pellucida impermeable to sperm. Before fertilization, the zona remains permeable because previously released ovastacin is inhibited by fetuin-B. Consequently, in the absence of fetuin-B, ZP2 cleavage occurs prematurely and leads to infertility of female fetuin-B deficient mice. In contrast, fetuin-B/ovastacin double-deficient oocytes show a permanently permeable zona with intact ZP2. In this study, we asked if the elastic modulus of the zona pellucida informs about ZP2 cleavage and thus could serve as a new reference of oocyte fertility. Therefore, we determined the elastic modulus of mouse oocytes by nanoindentation as a direct measure of mechanical zona hardening. The elastic modulus reflects ZP2 cleavage, but with more than double sensitivity compared to immunoblot analysis. The elastic modulus measurement allowed to define the range of zona hardening, confined by the extreme states of the zona pellucida in fetuin-B and ovastacin-deficient oocytes with cleaved and uncleaved ZP2, respectively. We present here nanoindentation as a method to quantify the effect of potential contributing factors on the zona hardening of individual oocytes. To demonstrate this, we showed that mechanical hardening of the zona pellucida is forced by recombinant ovastacin, inhibited by additional administration of fetuin-B, and unaffected by zinc. Since the change in elastic modulus is induced by ZP2 cleavage, an automated elastic modulus measurement of oocytes may serve as a novel sensitive, non-destructive, marker-free, and observer-unbiased method for assessing individual oocyte quality.

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31

Brown, C. R., e R. Jones. "Binding of zona pellucida proteins to a boar sperm polypeptide of Mr 53,000 and identification of zona moieties involved". Development 99, n. 3 (1 marzo 1987): 333–39. http://dx.doi.org/10.1242/dev.99.3.333.

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Abstract (sommario):

Experiments have been carried out to identify proteins on boar spermatozoa that bind to components of the zona pellucida. Polypeptides in sodium deoxycholate extracts of boar spermatozoa and in whole seminal plasma have been separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, transferred onto nitrocellulose sheet by electroblotting and probed with 125I-labelled heat-solubilized zona pellucida from pig oocytes or ovulated eggs. Zona proteins bound avidly and consistently to a polypeptide of Mr 53,000 on blots of capacitated and noncapacitated sperm and weakly to polypeptides of Mr 67,000, 38,000 and 18,000. On blots of seminal plasma the 125I-labelled probes bound to two polypeptides of Mr 65,000 and 19–24,000. Identification of the zona proteins that were binding to the aforementioned proteins on blots showed that all the major zona pellucida glycoproteins were involved, including those acquired from oviduct secretions. Binding of 125I-ovulated zona pellucida to the polypeptide of Mr 53,000 also occurred in extracts of testicular and epididymal boar spermatozoa. The results are discussed in relation to sperm-egg recognition in the pig.

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32

Epifano, O., e J. Dean. "Biology and structure of the zona pellucida: a target for immunocontraception". Reproduction, Fertility and Development 6, n. 3 (1994): 319. http://dx.doi.org/10.1071/rd9940319.

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Abstract (sommario):

Although reversible interference of sperm-egg interactions with pharmacological agents has not yet been achieved, animal models have provided increasing evidence that immunological reagents directed against mammalian gametes can effectively inhibit fertilization. One potential target of immunocontraception is the zona pellucida, an extracellular matrix that surrounds the growing oocyte and ovulated egg. Recent advances in our knowledge of the biosynthesis and molecular biology of the zona pellucida have provided much information useful in the rational design of immunocontraceptive vaccines. There remain, however, major obstacles to using immunological reagents to prevent fertilization, including potential toxic side effects, the lack of adequate delivery systems and the possibility of incomplete reversibility. This review summarizes current understanding of the production of the zona pellucida during folliculogenesis, the structure of the conserved proteins and genes in the zona pellucida, and the progress made in the development of immunocontraceptive strategies that focus on this oocyte-specific structure.

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33

Zhao, Longmei, Kerstin Reim e David J. Miller. "Complexin-I-deficient sperm are subfertile due to a defect in zona pellucida penetration". REPRODUCTION 136, n. 3 (settembre 2008): 323–34. http://dx.doi.org/10.1530/rep-07-0569.

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Abstract (sommario):

Upon adhesion to the zona pellucida, sperm undergo regulated exocytosis of the acrosome. Although it is necessary for sperm to penetrate the zona pellucida and fertilize an egg, the acrosomal membrane fusion process is poorly understood. Complexins I and II are small, cytosolic proteins that bind to a complex of proteins termed the solubleN-ethylmaleimide-sensitive factor attachment protein receptor complex to regulate synaptic vesicle exocytosis. Complexin-II-deficient mice are fertile but the fertility of sperm from complexin-I-deficient male mice is unclear because the mice have ataxia and cannot mate. Here, we show that the genes encoding complexins I and II are expressed in primary spermatocytes and spermatids. Complexin proteins were found in/near the developing acrosome in spermatids and in or around the acrosome of mature sperm. Cell fractionation demonstrated that complexins I and II were predominantly found in the cytosolic fraction. Furthermore, sperm from complexin-I-deficient mice had normal morphology, number, and only small differences in motility, as assessed by computer-assisted semen analysis. Complexin-I-deficient sperm capacitated normally and bound to the zona pellucida. But when sperm from complexin-I-deficient mice were inseminated into females, a defect in fertility was observed, in concordance with previous data showing thatin vitrofertilization rate was also reduced. If the zona pellucida was removed prior toin vitrofertilization, fertility was normal, demonstrating that zona pellucida penetration was defective, a step requiring acrosomal exocytosis. Therefore, complexin-I-deficient sperm are subfertile due to faulty zona pellucida penetration.

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Lai, AC, JP Ryan e DM Saunders. "Removal of the zona pellucida and parthenogenetic activation affect rates of survival of ultrarapidly frozen mouse oocytes". Reproduction, Fertility and Development 6, n. 6 (1994): 771. http://dx.doi.org/10.1071/rd9940771.

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Abstract (sommario):

Survival rates on thawing were assessed for ultrarapidly frozen mouse oocytes following the removal of zonae pellucidae using an acid Tyrode's solution, pronase or a mechanical dissection technique. Significantly higher rates of survival were observed for zona-free oocytes than for zona-intact control oocytes (303/684, 44% v. 130/498, 26%; P < 0.001). The rates of survival observed for pronuclear stage embryos (72-76%) were much greater than those observed for oocytes and were not influenced by zona removal techniques. Parthenogenetic activation of oocytes by exposure to a 7% (v/v) ethanol solution was also shown to increase survival rates of ultrarapidly frozen oocytes (155/185, 84% v. 19/102, 19%) indicating that fusion of sperm to the plasma membrane or formation of a male pronucleus are not directly responsible for the increased survival rates of pronuclear stage embryos compared with oocytes. These data support the hypothesis that increased survival of ultrarapidly frozen pronuclear stage embryos is the result of changes to the plasma membrane and/or to the zona pellucida that occur following fertilization.

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Gu, Yi-Fan, Chang-Fu Lu, Ge Lin e Guang-Xiu Lu. "A comparative analysis of the zona pellucida birefringence of fresh and frozen–thawed human embryos". REPRODUCTION 139, n. 1 (gennaio 2010): 121–27. http://dx.doi.org/10.1530/rep-09-0227.

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Abstract (sommario):

The cryopreservation of human embryos is thought to induce alteration in the glycoprotein matrix and lead to zona change. However, this assumption has been full of controversies till now. The objective of this study was to evaluate the effect of cryopreservation on zona pellucida of human embryos. Fresh (n=106, from 40 patients) and frozen–thawed embryos (n=123, from 40 patients) were obtained from consenting patients who received conventional IVF and ICSI treatment. The birefringence of zona pellucida in human fresh and frozen–thawed embryos was imaged and quantitatively analyzed using polarized light microscopy before embryo transfer. There was no significant difference in retardance and thickness of the zona pellucida multilaminar structure between the two groups. Pregnancy and implantation rates of transferred fresh and frozen–thawed embryos were also compared. No significant difference was found in the rates of clinical pregnancy (47.5 vs 37.5%) and implantation (24.5 vs 23.2%) between the two groups. This study suggests that there is no significant change in the zona pellucida birefringence of human embryos before and after cryopreservation.

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Hino, Toshiaki, Kanako Oda, Kenji Nakamura, Hiroyuki Tateno, Yutaka Toyoda e Minesuke Yokoyama. "Accelerated modification of the zona pellucida is the primary cause of decreased fertilizability of oocytes in the 129 inbred mouse strain". Zygote 19, n. 4 (21 dicembre 2010): 315–22. http://dx.doi.org/10.1017/s0967199410000481.

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Abstract (sommario):

SummaryWe investigated whether the small litter size in the 129 inbred mouse strain results from a reduction in oocyte fertilizability. Sensitivity of the zona pellucida to α-chymotrypsin was examined for oocytes collected at 14 h (shortly after ovulation), 17 h, and 20 h after hCG injection. Passage of spermatozoa through the zona pellucida (using an in vitro fertilization (IVF) technique) and the density of cortical granules were examined for oocytes collected at 14 and 17 h after hCG injection. The capability of the oolemma to fuse with the sperm plasma membrane was also evaluated by IVF using zona-free eggs. The zona pellucida became markedly resistant to the enzyme 17 h after hCG injection. IVF rates significantly decreased at this time. In addition, there was a significant reduction in the density of cortical granules. When zona-free oocytes were inseminated, high fertilization rates were obtained at both 17 and 14 h after hCG injection. These results indicate that accelerated modification of the zona pellucida primarily causes a decreased fertilizability of oocytes in 129 mice, resulting in the low reproductive performance of this strain.

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37

Kim, Jungsik, e Jung Kim. "Viscoelastic Characterization of Mouse Zona Pellucida". IEEE Transactions on Biomedical Engineering 60, n. 2 (febbraio 2013): 569–75. http://dx.doi.org/10.1109/tbme.2012.2230444.

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38

Wassarman, P. M., L. Jovine e E. S. Litscher. "Mouse zona pellucida genes and glycoproteins". Cytogenetic and Genome Research 105, n. 2-4 (2004): 228–34. http://dx.doi.org/10.1159/000078193.

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39

Wassarman, Paul M., e Eveline S. Litscher. "Mammalian fertilization:the eggs multifunctional zona pellucida". International Journal of Developmental Biology 52, n. 5-6 (2008): 665–76. http://dx.doi.org/10.1387/ijdb.072524pw.

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40

Sinowatz, F., E. Topfer-Petersen, S. Kolle e G. Palma. "Functional Morphology of the Zona Pellucida". Anatomia, Histologia, Embryologia: Journal of Veterinary Medicine Series C 30, n. 5 (ottobre 2001): 257–63. http://dx.doi.org/10.1046/j.1439-0264.2001.00337.x.

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41

Litscher, Eveline S., e Paul M. Wassarman. "Zona Pellucida Proteins, Fibrils, and Matrix". Annual Review of Biochemistry 89, n. 1 (20 giugno 2020): 695–715. http://dx.doi.org/10.1146/annurev-biochem-011520-105310.

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Abstract (sommario):

The zona pellucida (ZP) is an extracellular matrix that surrounds all mammalian oocytes, eggs, and early embryos and plays vital roles during oogenesis, fertilization, and preimplantation development. The ZP is composed of three or four glycosylated proteins, ZP1–4, that are synthesized, processed, secreted, and assembled into long, cross-linked fibrils by growing oocytes. ZP proteins have an immunoglobulin-like three-dimensional structure and a ZP domain that consists of two subdomains, ZP-N and ZP-C, with ZP-N of ZP2 and ZP3 required for fibril assembly. A ZP2–ZP3 dimer is located periodically along ZP fibrils that are cross-linked by ZP1, a protein with a proline-rich N terminus. Fibrils in the inner and outer regions of the ZP are oriented perpendicular and parallel to the oolemma, respectively, giving the ZP a multilayered appearance. Upon fertilization of eggs, modification of ZP2 and ZP3 results in changes in the ZP's physical and biological properties that have important consequences. Certain structural features of ZP proteins suggest that they may be amyloid-like proteins.

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42

Bauskin, A. R. "Characterization of human zona pellucida glycoproteins". Molecular Human Reproduction 5, n. 6 (1 giugno 1999): 534–40. http://dx.doi.org/10.1093/molehr/5.6.534.

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43

Mahony, Mary C., Karen Rice, Erwin Goldberg e Gustavo Doncel. "Baboon spermatozoa–zona pellucida binding assay". Contraception 61, n. 3 (marzo 2000): 235–40. http://dx.doi.org/10.1016/s0010-7824(00)00093-7.

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44

Barros, C., C. Capote, C. Pérez, J. Crosby, M. I. Becker e A. De Ioannes. "Sperm passage through the zona pellucida". Proceedings, annual meeting, Electron Microscopy Society of America 48, n. 3 (12 agosto 1990): 54–55. http://dx.doi.org/10.1017/s0424820100157814.

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Sperm passage through the zona pellucida requires the occurrence of the acrosome reaction. This latter reaction, in turn, is supposedly needed to release the acrosomal enzymes, particularly acrosin which has been involved in the sperm binding to and penetration through the zona pellucida. The application of the immunogold technique using the monoclonal antiacrosin antibody ACR-C2E5 allowed us to identify acrosin in hamster, human and guinea-pig spermatozoa at the optic and scanning electron microscope, in which the immunogold labelling was silver enhanced. At the transmition electron microscope the monoclonal antibody was indirectly labelled with 10nm gold particles. In hamster spermatozoa there were three patterns of labelling: a) either no labelling, or an intense one over acrosomal region of apparently acrosome intact spermatozoa (Figures la,b, 2a & 3a); b) an intense labelling over the inner acrosomal surface and on the acrosomal cap of acrosome reacted spermatozoa (Figures lc,d, 2b & 3b); and c) either a slight labelling over the equatorial region or no labelling on acrosome reacted spermatozoa (Figure le,f,2c).

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45

Papi, Massimiliano, Giuseppe Arcovito e Marco De Spirito. "Physical Properties of the Zona Pellucida". Biophysical Journal 96, n. 3 (febbraio 2009): 337a. http://dx.doi.org/10.1016/j.bpj.2008.12.3816.

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46

Mori, T., M. Kamada, H. Hasebe, M. Irahara, A. Shivers, A. B. Czuppon, L. Mettler, S. Mathur e B. S. Dunbar. "Antibody reactivity with porcine zona pellucida". Journal of Reproductive Immunology 8, n. 4 (dicembre 1985): 337–45. http://dx.doi.org/10.1016/0165-0378(85)90008-7.

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47

Dietl, Johannes. "Die Zona pellucida des S�ugetiereies". Naturwissenschaften 73, n. 2 (febbraio 1986): 89–94. http://dx.doi.org/10.1007/bf00365833.

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48

Papi, Massimiliano, Roberto Brunelli, Lakamy Sylla, Tiziana Parasassi, Maurizio Monaci, Giuseppe Maulucci, Mauro Missori, Giuseppe Arcovito, Fulvio Ursini e Marco De Spirito. "Mechanical properties of zona pellucida hardening". European Biophysics Journal 39, n. 6 (27 maggio 2009): 987–92. http://dx.doi.org/10.1007/s00249-009-0468-3.

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49

Topper, E. K., L. Kruijt, J. Calvete, K. Mann, E. Töpfer-Petersen e H. Woelders. "Identification of bovine zona pellucida glycoproteins". Molecular Reproduction and Development 46, n. 3 (marzo 1997): 344–50. http://dx.doi.org/10.1002/(sici)1098-2795(199703)46:3<344::aid-mrd13>3.0.co;2-z.

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50

Redgrove, K. A., E. A. McLaughlin, M. K. O'Bryan, R. J. Aitken e B. Nixon. "168. IDENTIFICATION AND CHARACTERISATION OF SURFACE PROTEIN COMPLEXES IN HUMAN SPERMATOZOA". Reproduction, Fertility and Development 21, n. 9 (2009): 86. http://dx.doi.org/10.1071/srb09abs168.

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Abstract (sommario):

Upon leaving the testis mammalian spermatozoa are functionally incompetent and are thus unable to fertilize an oocyte. As the spermatozoa ascend the female reproductive tract, functional maturity is achieved through a complex cascade of biophysical and biochemical changes known as capacitation. An important aspect of this final maturation phase is the remodelling of the sperm surface architecture to enable it to interact with the zona pellucida, a glycoprotein matrix that surrounds the oocyte, and initiate fertilisation. While originally thought to be underpinned by a simple lock and key mechanism, emerging evidence has suggested that this interaction may instead be mediated by a multimeric recognition complex that is formed on the sperm surface during capacitation. However, to date the presence and composition of such a complex has yet to be described. Through the application of Blue Native Polyacrylamide Gel Electrophoresis (BN-PAGE), we have provided evidence that human spermatozoa express a number of high molecular weight protein complexes on their surface. Furthermore, the affinity of these surface expressed complexes for the zona pellucida was assessed utilising solubilised human zona pellucida and the technique of Far Western Blotting. Among the complexes that showed affinity for the zona pellucida we identified one comprising 14 subunits of the 20S proteasome. Interestingly, the 20S proteasome has previously been implicated in various aspects of mammalian fertilisation, including zona pellucida penetration and the acrosome reaction, although its precise role in these events has yet to be elucidated. Collectively, these results demonstrate the presence of multimeric protein complexes on the surface of human spermatozoa, and support their putative role in the initial interaction between the sperm and the zona pellucida. Our current research is focused on elucidation of the role of the 20S proteasome in human sperm-zona binding and further investigation of surface expressed protein complexes.

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