Dataset Information

A truncating MEIOB mutation responsible for familial primary ovarian insufficiency abolishes its interaction with its partner SPATA22 and their recruitment to DNA double-strand breaks.

ABSTRACT:

Background

Primary Ovarian Insufficiency (POI), a major cause of infertility, affects about 1-3% of women under forty years of age. Although there is a growing list of causal genetic alterations, POI remains mostly idiopathic.

Methods

We performed exome sequencing (WES) of two sisters affected with POI, one unaffected sister and their mother from a consanguineous family. We assessed the impact of the identified MEIOB variant with a minigene assay and by sequencing illegitimate transcripts from the proband's leukocytes. We studied its functional impact on the interaction between MEIOB with its partner SPATA22 and their localization to DNA double-strand breaks (DSB).

Findings

We identified a homozygous variant in the last base of exon 12 of MEIOB, which encodes a factor essential for meiotic recombination. This variant was predicted to strongly affect MEIOB pre-mRNA splicing. Consistently, a minigene assay showed that the variant induced exon 12 skipping, which was confirmed in vivo in the proband's leukocytes. Aberrant splicing leads to the production of a C-terminally truncated protein that cannot interact with SPATA22, abolishing their recruitment to DSBs.

Interpretation

This truncating MEIOB variant is expected to provoke meiotic defects and a depleted follicular stock, as in Meiob^-/- mice. This is the first molecular defect reported in a meiosis-specific single-stranded DNA-binding protein (SSB) responsible for POI. We hypothesise that alterations in other SSB proteins could explain cases of syndromic or isolated ovarian insufficiency. FUND: Université Paris Diderot, Fondation pour la Recherche Médicale, Fondation ARC contre le cancer, Commissariat à l'Energie Atomique and Institut Universitaire de France.

SUBMITTER: Caburet S

PROVIDER: S-EPMC6491878 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A truncating MEIOB mutation responsible for familial primary ovarian insufficiency abolishes its interaction with its partner SPATA22 and their recruitment to DNA double-strand breaks.

Caburet Sandrine S Todeschini Anne-Laure AL Petrillo Cynthia C Martini Emmanuelle E Farran Nada D ND Legois Bérangère B Livera Gabriel G Younis Johnny S JS Shalev Stavit S Veitia Reiner A RA

EBioMedicine 20190415

<h4>Background</h4>Primary Ovarian Insufficiency (POI), a major cause of infertility, affects about 1-3% of women under forty years of age. Although there is a growing list of causal genetic alterations, POI remains mostly idiopathic.<h4>Methods</h4>We performed exome sequencing (WES) of two sisters affected with POI, one unaffected sister and their mother from a consanguineous family. We assessed the impact of the identified MEIOB variant with a minigene assay and by sequencing illegitimate tra ...[more]

PMID: 31000419

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Project description:BACKGROUND & AIMS:DNA structural lesions are prevalent in sporadic colorectal cancer. Therefore, we proposed that gene variants that predispose to DNA double-strand breaks (DSBs) would be found in patients with familial colorectal carcinomas of an undefined genetic basis (UFCRC). METHODS:We collected primary T cells from 25 patients with UFCRC and matched patients without colorectal cancer (controls) and assayed for DSBs. We performed exome sequence analyses of germline DNA from 20 patients with UFCRC and 5 undiagnosed patients with polyposis. The prevalence of identified variants in genes linked to DNA integrity was compared with that of individuals without a family history of cancer. The effects of representative variants found to be associated with UFCRC was confirmed in functional assays with HCT116 cells. RESULTS:Primary T cells from most patients with UFCRC had increased levels of the DSB marker γ(phosphorylated)histone2AX (γH2AX) after treatment with DNA damaging agents, compared with T cells from controls (P < .001). Exome sequence analysis identified a mean 1.4 rare variants per patient that were predicted to disrupt functions of genes relevant to DSBs. Controls (from public databases) had a much lower frequency of variants in the same genes (P < .001). Knockdown of representative variant genes in HCT116 CRC cells increased γH2AX. A detailed analysis of immortalized patient-derived B cells that contained variants in the Werner syndrome, RecQ helicase-like gene (WRN, encoding T705I), and excision repair cross-complementation group 6 (ERCC6, encoding N180Y) showed reduced levels of these proteins and increased DSBs, compared with B cells from controls. This phenotype was rescued by exogenous expression of WRN or ERCC6. Direct analysis of the recombinant variant proteins confirmed defective enzymatic activities. CONCLUSIONS:These results provide evidence that defects in suppression of DSBs underlie some cases of UFCRC; these can be identified by assays of circulating lymphocytes. We specifically associated UFCRC with variants in WRN and ERCC6 that reduce the capacity for repair of DNA DSBs. These observations could lead to a simple screening strategy for UFCRC, and provide insight into the pathogenic mechanisms of colorectal carcinogenesis.

Dataset Information

A truncating MEIOB mutation responsible for familial primary ovarian insufficiency abolishes its interaction with its partner SPATA22 and their recruitment to DNA double-strand breaks.

Background

Methods

Findings

Interpretation

Publications

A truncating MEIOB mutation responsible for familial primary ovarian insufficiency abolishes its interaction with its partner SPATA22 and their recruitment to DNA double-strand breaks.

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