title: Homozygous mutation of PLCZ1 leads to defective human oocyte activation and infertility that is not rescued by the WW-binding protein PAWP.
abstract: In mammals, sperm-oocyte fusion initiates Ca(2+) oscillations leading to a series of events called oocyte activation, which is the first stage of embryo development. Ca(2+) signaling is elicited by the delivery of an oocyte-activating factor by the sperm. A sperm-specific phospholipase C (PLCZ1) has emerged as the likely candidate to induce oocyte activation. Recently, PAWP, a sperm-born tryptophan domain-binding protein coded by WBP2NL, was proposed to serve the same purpose. Here, we studied two infertile brothers exhibiting normal sperm morphology but complete fertilization failure after intracytoplasmic sperm injection. Whole exomic sequencing evidenced a missense homozygous mutation in PLCZ1, c.1465A>T; p.Ile489Phe, converting Ile 489 into Phe. We showed the mutation is deleterious, leading to the absence of the protein in sperm, mislocalization of the protein when injected in mouse GV and MII oocytes, highly abnormal Ca(2+) transients and early embryonic arrest. Altogether these alterations are consistent with our patients' sperm inability to induce oocyte activation and initiate embryo development. In contrast, no deleterious variants were identified in WBP2NL and PAWP presented normal expression and localization. Overall we demonstrate in humans, the absence of PLCZ1 alone is sufficient to prevent oocyte activation irrespective of the presence of PAWP. Additionally, it is the first mutation located in the C2 domain of PLCZ1, a domain involved in targeting proteins to cell membranes. This opens the door to structure-function studies to identify the conserved amino acids of the C2 domain that regulate the targeting of PLCZ1 and its selectivity for its lipid substrate(s).
authors.affiliation: Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland.
authors.forename: Jessica
authors.initials: J
authors.lastname: Escoffier
authors.affiliation: Department of Veterinary and Animal Sciences and.
authors.forename: Hoi Chang
authors.initials: HC
authors.lastname: Lee
authors.affiliation: Université Grenoble Alpes, Grenoble, F-38000, Grenoble, France, Institut Albert Bonniot, INSERM U823, La Tronche F-38700, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Yassine
authors.affiliation: Polyclinique les Jasmins, Centre d'Aide Médicale à la Procréation, Centre Urbain Nord, 1003 Tunis, Tunisia.
authors.forename: Raoudha
authors.initials: R
authors.lastname: Zouari
authors.affiliation: Université Grenoble Alpes, Grenoble, F-38000, Grenoble, France, Institut Albert Bonniot, INSERM U823, La Tronche F-38700, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Martinez
authors.affiliation: Université Grenoble Alpes, Grenoble, F-38000, Grenoble, France, Institut Albert Bonniot, INSERM U823, La Tronche F-38700, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Karaouzène
authors.affiliation: Université Grenoble Alpes, Grenoble, F-38000, Grenoble, France, CHU de Grenoble, UF de Génétique Chromosomique, Grenoble F-38000, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Coutton
authors.affiliation: Université Grenoble Alpes, Grenoble, F-38000, Grenoble, France, Institut Albert Bonniot, INSERM U823, La Tronche F-38700, France.
authors.forename: Zine-Eddine
authors.initials: ZE
authors.lastname: Kherraf
authors.affiliation: Polyclinique les Jasmins, Centre d'Aide Médicale à la Procréation, Centre Urbain Nord, 1003 Tunis, Tunisia.
authors.forename: Lazhar
authors.initials: L
authors.lastname: Halouani
authors.affiliation: Clinique Hannibal, Centre d'AMP, les berges du lac, 1053 Tunis, Tunisia.
authors.forename: Chema
authors.initials: C
authors.lastname: Triki
authors.affiliation: Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland.
authors.forename: Serge
authors.initials: S
authors.lastname: Nef
authors.affiliation: Université Grenoble Alpes, Grenoble, F-38000, Grenoble, France, Laboratoire TIMC-IMAG, UMR CNRS 5525, Grenoble F-38000, France and.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Thierry-Mieg
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Savinov
authors.affiliation: Department of Veterinary and Animal Sciences and.
authors.forename: Rafael
authors.initials: R
authors.lastname: Fissore
authors.affiliation: Université Grenoble Alpes, Grenoble, F-38000, Grenoble, France, Institut Albert Bonniot, INSERM U823, La Tronche F-38700, France, CHU de Grenoble, UF de Biochimie et Génétique Moléculaire, Grenoble F-38000, France.
authors.forename: Pierre F
authors.initials: PF
authors.lastname: Ray
authors.affiliation: Université Grenoble Alpes, Grenoble, F-38000, Grenoble, France, Institut Albert Bonniot, INSERM U823, La Tronche F-38700, France, christophe.arnoult@ujf-grenoble.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Arnoult
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020013:Calcium Signaling; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D020964:Embryo Loss; D005260:Female; D005786:Gene Expression Regulation; D006720:Homozygote; D006801:Humans; D059471:In Vitro Oocyte Maturation Techniques; D007248:Infertility, Male / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D054801:Phosphoinositide Phospholipase C / Q000172:deficiency / Q000235:genetics*; D021381:Protein Transport; D029589:Seminal Plasma Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D035781:Siblings; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions / Q000235:genetics*; D013094:Spermatozoa / Q000378:metabolism* / Q000473:pathology
chemical_list: D002352:Carrier Proteins; D029589:Seminal Plasma Proteins; C519840:WBP2NL protein, human; C499235:PLCZ1 protein, human; D054801:Phosphoinositide Phospholipase C