Homozygous mutation of PLCZ1 leads to defective human oocyte activation and infertility that is not rescued by the WW-binding protein PAWP.
Hum Mol Genet
; 25(5): 878-91, 2016 Mar 01.
Article
en En
| MEDLINE
| ID: mdl-26721930
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).
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Interacciones Espermatozoide-Óvulo
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Espermatozoides
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Proteínas Portadoras
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Proteínas de Plasma Seminal
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Fosfoinositido Fosfolipasa C
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Infertilidad Masculina
/
Mutación
Tipo de estudio:
Prognostic_studies
Límite:
Adult
/
Animals
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Female
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Humans
/
Male
Idioma:
En
Revista:
Hum Mol Genet
Asunto de la revista:
BIOLOGIA MOLECULAR
/
GENETICA MEDICA
Año:
2016
Tipo del documento:
Article
País de afiliación:
Suiza