title: Dicalcin, a zona pellucida protein that regulates fertilization competence of the egg coat in Xenopus laevis.
abstract: Fertilization is a highly coordinated process whereby sperm interact with the egg-coating envelope (called the zona pellucida, ZP) in a taxon-restricted manner, Fertilization triggers the resumption of the cell cycle of the egg, ultimately leading to generation of a new organism that contains hereditary information of the parents. The complete sperm-ZP interaction comprises sperm recognition of the ZP, the acrosome reaction, penetration of the ZP, and fusion with the egg. Recent evidence suggests that these processes involve oligosaccharides associated with a ZP constituent (termed ZP protein), the polypeptide backbone of a ZP protein, and/or the proper three-dimensional filamentous structure of the ZP. However, a detailed description of the molecular mechanisms involved in sperm-ZP interaction remains elusive. Recently, I found that dicalcin, a novel ZP protein-associated protein, suppresses fertilization through its association with gp41, the frog counterpart of the mammalian ZPC protein. This review focuses on molecular aspects of sperm-ZP interaction and describes the fertilization-suppressive function of dicalcin and associated molecular mechanisms. The amount of dicalcin in the ZP significantly correlates with alteration of the lectin-staining pattern within the ZP and the orientation pattern of ZP filaments, which may assist in elucidating the complex molecular mechanisms that underlie sperm-ZP interaction.
authors.affiliation: Department of Physiology, School of Medicine, Toho University, Tokyo, Japan. nmiwa@med.toho-u.ac.jp.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Miwa
mesh_terms: D000818:Animals; D005306:Fertilization / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D009418:S100 Proteins / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000502:physiology*; D015044:Zona Pellucida / Q000502:physiology*
chemical_list: D009418:S100 Proteins; C525113:S100A11 protein, Xenopus; D029867:Xenopus Proteins
keywords: Egg-coating envelope; Fertilization; Sperm; ZP protein