Children's Hospital and Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China.
Zhuhai Fudan Innovation Institute, Zhuhai, China.
J Med Genet. 2020 Mar;57(3):187-194. doi: 10.1136/jmedgenet-2019-106379. Epub 2019 Nov 8.
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.
We aim to identify genetic factors responsible for multiple pronuclei formation during fertilisation or early embryonic arrest.
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.
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 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 , 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.
Our study has identified mutations in 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.
受精过程中异常原核形成和随后的早期胚胎阻滞导致女性不孕。近年来，随着辅助生殖技术的普及，已经确定了一些与卵母细胞发育、受精和胚胎发育异常导致的女性不孕有关的基因。然而，导致受精过程中多原核形成和早期胚胎阻滞的遗传因素在很大程度上仍然未知。
我们旨在鉴定导致受精过程中多原核形成或早期胚胎阻滞的遗传因素。
对 580 例受精异常和早期胚胎阻滞患者进行全外显子组测序。通过 Western blot 和免疫沉淀以及小基因试验在 HEK293T 细胞中研究突变的影响。
我们在减数分裂基因 REC114 中发现了一个新的纯合错义突变（c.397T>G，p.C133G）和一个新的纯合供体位点突变（c.546+5G>A）。REC114 参与双链断裂（DSB）的形成，DSB 启动同源染色体重组。我们证明，剪接位点突变影响 的正常选择性剪接，而错义突变降低了体外 REC114 的蛋白水平，并导致其保护其伴侣蛋白 MEI4 免于降解的功能丧失。
我们的研究鉴定了 REC114 基因中的突变，这些突变导致了人类多原核形成和早期胚胎阻滞，这些发现扩展了我们对导致正常人类女性减数分裂和生育能力的遗传因素的认识。
