母源因子Filia在卵细胞DNA损伤反应中的作用及机制的研究

Germ cells are carriers of information among generations, and the genomic stability of germ cells ensures that species could produce health offspring and reproduce successfully. Cellular endogenous and exogenous toxins often lead to DNA damage of cells which may induce a reaction-DNA damage response (DDR). DDR is a complex system of damage detection and repair in order to preserve the integrity of genome. How to maintain the integrity of genome by DDR is critical for germ cells, but surprisingly little is known about DDR in germ cells. Our previous data show that a maternal factor Filia plays a role to maintain correct chromosome number in mouse preimplantation embryos. Transcripts of Filia express abundantly in oocytes, and its proteins are present stably in preimplantation embryos. Depletion of Filia leads to impair development of early embryos with a high incidence of aneuploidy, but the mechanism is not clarified. We found Filia also express in mouse embryonic stem cells (mESCs), considering that embryonic stem cells have similar developmental potential and mechanism of cellular regulation with oocytes, and so we use mESCs to investigate functions of Filia. We found that Filia regulate DDR in mESCs in order to preserve genomic stability. Using an anticancer drug etoposide, we develop a model of DNA double strand break. In our model, Filia deficient oocytes can not repair DNA damage efficiently induced by etoposide. These preliminary data indicate that Filia may have an unknown role to regulate DDR in oocytes and preimplantation embryos. Our project is ready to investigate whether Filia participate in DDR regulation in oocytes and preimplantation embryos to maintain genomic integrity and the function and mechanism in regulating DDR of Filia would be explored priliminarily.

生殖细胞是新个体产生的物质基础，其遗传物质稳定性的维持对物种产生健康的后代和成功繁衍致关重要。DNA损伤反应（DDR）是维持细胞遗传物质稳定性的重要机制。生殖细胞如何维持其遗传物质的稳定是非常重要但又了解甚少的重要科学问题。我们前期工作揭示小鼠卵细胞中的母源因子Filia参与维持早期胚胎染色体数目的稳定。Filia也在胚胎干细胞中特异表达，卵细胞和胚胎干细胞在发育潜能和调控机制上有很大的相似性，我们发现Filia基因在胚胎干细胞中可以通过调控DNA损伤反应而维持遗传物质的稳定性。我们通过etoposide处理卵细胞建立DNA损伤模型，初步结果显示Filia-/-卵细胞不能有效修复DNA损伤，提示Filia蛋白可能在卵细胞和早期胚胎中参与DNA损伤反应。本项目将详细研究Filia是否在卵细胞及早期胚胎中通过参与调控DNA损伤反应，从而维持配子及早期胚胎遗传物质的稳定性，并初步探讨其作用机制。