Browsing by Subject "Zona pellucida"

Now showing 1 - 4 of 4
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    New Insights into the Mammalian Egg Zona Pellucida
    (2021) Chevret, Pascale; Algarra, Blanca; González-Brusi, Leopoldo; Cots Rodríguez, Paula; Izquierdo Rico, María José; Avilés Sánchez, Manuel; Jíménez Movilla, María; Moros Nicolás, Carla; Biología Celular e Histología
    Mammalian oocytes are surrounded by an extracellular coat called the zona pellucida (ZP), which, from an evolutionary point of view, is the most ancient of the coats that envelope vertebrate oocytes and conceptuses. This matrix separates the oocyte from cumulus cells and is responsible for species-specific recognition between gametes, preventing polyspermy and protecting the preimplantation embryo. The ZP is a dynamic structure that shows different properties before and after fertilization. Until very recently, mammalian ZP was believed to be composed of only three glycoproteins, ZP1, ZP2 and ZP3, as first described in mouse. However, studies have revealed that this composition is not necessarily applicable to other mammals. Such differences can be explained by an analysis of the molecular evolution of the ZP gene family, during which ZP genes have suffered pseudogenization and duplication events that have resulted in differing models of ZP protein composition. The many discoveries made in recent years related to ZP composition and evolution suggest that a compilation would be useful. Moreover, this review analyses ZP biosynthesis, the role of each ZP protein in different mammalian species and how these proteins may interact among themselves and with other proteins present in the oviductal lumen.
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    Ovarian development in mice bearing homozygous or heterozygous null mutations in zona pellucida glycoprotein gene mZP3
    (Murcia : F. Hernández, 1998) Wassarman, P.M.; Liu, C.; Chen, J.; Qi, H.; Litscher, E.S.
    The plasma membrane of all mammalian eggs is surrounded by a thick extracellular coat, the zonu pellirc.id(i (ZP), whose paramount function is to regulate species-specific fertilization. The mouse egg ZP is composed of only three glycoproteins, mZPI -3, that are synthesized and secreted exclusively by oocytes during their 2-3 week growth phase. Disruption of the rnZP3 gene by targeted mutagenesis in embryonic stem (ES) cells yields mice heterozygous ( r n ~ P 3 + / -o)r hornozygous ( r n ~ P 3 - / -f)o r the null mutation. As expected, male mice bearing the null mutation are indistinguishable from wild-type males with respect to viability and fertility. Female m ~ ~ 3 +m/ic-e are as fertile as wild-type animals, but their eggs have a thin ZP (-2.7 pm thick) as compared to the ZP (-6.2 pm thick) of eggs from wild-type animals. On the other hand, female rn~P3-/m- ice are infertile and their eggs lack a ZP. The infertility apparently is due to the lack of a sufficient number of eggs in oviducts of superovulated ~ZPJ-lfemales. Light micrographs reveal that development of ovarian follicles is often retarded in rnz~3- l -m ice as compared to wild-type animals. This is manifested as reduced ovarian weights, reduced numbers of Graafian follicles, and reduced numbers of fully-grown oocytes in I ~ Z P ~ -f/em- ales. I t seems likely that the pleiotropic effects of the homozygous null mutation on ovarian development may be due, at least in part, to disruption of intercellular communication between growing oocytes and their surrounding follicle cells.
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    Rabbit zona pellucida composition: A molecular, proteomic and phylogenetic approach
    (2012) Stetson, I.; Chevret, P.; Lorenzo, P.L.; Ballesta, J.; Rebollar, P.G.; Gutiérrez-Gallego, R.; Izquierdo Rico, María José; Avilés Sánchez, Manuel; Moros Nicolás, Carla; Biología Celular e Histología
    The zona pellucida (ZP) participates in sperm–egg interactions during the first steps of 22 fertilization. Recent studies have shown that the ZP matrix of oocytes in several species is 23 composed of four glycoproteins, designated as ZP1, ZP2, ZP3 and ZP4, rather than the three 24 described in mouse, pig and cow. In this study, investigations were carried out to unveil a Q425 fourth glycoprotein in the rabbit (Oryctolagus cuniculus) ZP. Using total RNA isolated from 26 rabbit ovaries, the complementary deoxyribonucleic acid (cDNA) encoding rabbit ZP1 was 27 amplified by reverse transcribed polymerase chain reaction (RT-PCR). The ZP1 cDNA 28 contains an open reading frame of 1825 nucleotides encoding a polypeptide of 608 amino 29 acid residues. The deduced amino acid sequence of rabbit ZP1 showed high identity with 30 other species: 70% identity with human and horse ZP1, and 67% identity with mouse and rat 31 ZP1. At the proteomic level, peptides corresponding to the four proteins were detected by 32 mass spectrometry. In addition, a molecular phylogenetic analysis of ZP1 showed that 33 pseudogenization of this gene has occurred at least four times during the evolution of 34 mammals. The data presented in this manuscript provide evidence, for the first time, that 35 the rabbit ZP is composed of four glycoproteins.
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    The role of carbohydrate residues in mammalian fertilization
    (Murcia : F. Hernández, 1997) Shalgi, R.; Raz, T.
    The fertilization process in mammals involves binding and fusion of free-swimming sperm and ovulated eggs. This review focuses on the role of carbohydrate residues in the process of sperm-egg interaction in mammals. The zona pellucida (ZP), the acellular glycoprotein coat surrounding the egg is highly glycosylated and posssess both Asn- (N-) linked and SerlThr- (O-)linked oligosaccharides, with an extreme structural heterogeneity between the different species. Different carbohydrates on ZP3, such as Galactose in a-linkage, N-acetylglucosamine in B-linkage, were suggested as the complementary sperm receptors, mediating the primary binding between the spermatozoon and the ZP. Several suggested complementary ZP3 binding proteins on the sperm are sp56, O-1,4-galactosyltransferase and p95. Some carbohydrate residues of the ZP undergo postfertilization modifications that might alter the sperm receptor, thus assisting in the establishment of the block to polyspermy. The studies summarized in this review imply a main role for the carbohydrate residues in the process of sperm egg interaction.