Background Abnormal pronuclear formation during fertilisation and subsequent early embryonic arrest results in female infertility. In recent years, with the prevalence of assisted reproductive technology, a few genes have been identified that are involved in female infertility caused by abnormalities in oocyte development, fertilisation and embryonic development. However, the genetic factors responsible for multiple pronuclei formation during fertilisation and early embryonic arrest remain largely unknown.
Objective We aim to identify genetic factors responsible for multiple pronuclei formation during fertilisation or early embryonic arrest.
Methods Whole-exome sequencing was performed in a cohort of 580 patients with abnormal fertilisation and early embryonic arrest. Effects of mutations were investigated in HEK293T cells by western blotting and immunoprecipitation, as well as minigene assay.
Results We identified a novel homozygous missense mutation (c.397T>G, p.C133G) and a novel homozygous donor splice-site mutation (c.546+5G>A) in the meiotic gene REC114. REC114 is involved in the formation of double strand breaks (DSBs), which initiate homologous chromosome recombination. We demonstrated that the splice-site mutation affected the normal alternative splicing of REC114, while the missense mutation reduced the protein level of REC114 in vitro and resulted in the loss of its function to protect its partner protein MEI4 from degradation.
Conclusions Our study has identified mutations in REC114 responsible for human multiple pronuclei formation and early embryonic arrest, and these findings expand our knowledge of genetic factors that are responsible for normal human female meiosis and fertility.
- Female infertility
- Early embryonic arrest
- Mendelian disease
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WW, JD and BC are joint first authors.
Contributors WW, JDo and BC contributed equally to this work. WW, JDo, Z Zhang, QS and LWa conceived and designed this study. WW, JDo, BC, JDu, YK, XS, JF, BL, LWu, XM and ZY collected the samples. WW, BC, XM and JF organised the medical records. WW and JDo performed the experiments. WW, JDo, BC, JDu, JM, Z Zhang, Z Zhou, ZL, QL, LH, QS and LWa analysed the data. WW and LWa wrote the manuscript. All authors reviewed and approved the manuscript.
Funding This work was supported by the National Key Research and Development Program of China (2018YFC1003800; 2017YFC1001500; 2016YFC1000600), the National Natural Science Foundation of China (81725006, 81822019, 81771581, 81571501), Shanghai Municipal Science and Technology Major Project (2017SHZDZX01), the Shanghai Rising Star Program (17QA1400200), the Natural Science Foundation of Shanghai (17ZR1401900) and the Foundation of Shanghai Health and Family Planning Commission (20154Y0162).
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. Main data relevant to the study are included in the article or uploaded as supplementary information.
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