人类八细胞胚胎到早期囊胚发育过程中卵裂球异质性的研究

When the cells of a mammalian embryo first start to have differences and whether the first differences contribute to the cell fate specification remain key open questions and keep causing hot discussions among reproduction scientists. In mouse, the expression levels of some core transcriptional factors like Sox21 are highly heterogenous between blastomeres in the 4-cell embryo. Yet, during human pre-implantation development, when the heterogeneity among blastomeres of one embryo arising and how the initial differences playing roles in cell fate decision are still unknown..Based on our previous research and analysis on the patterns of transcriptome and methylome in human pre-implantation embryos, this project will capture the transcriptome, genome and methylome simultaneously, in every single blastomere of an embryo from 8-cell to unhatched blastocyst during human pre-implantation development with scTrio-seq. By comparing the gene expression and DNA modification within embryos following successive stages, the timeline and characteristics of blastomere heterogeneity will be clarified, and the core transcriptional and epigenetic factors which play crucial roles in regulating the cell fate in human embryo would come to light..Characterizing the heterogeneity among blastomeres within an embryo from 8-cell to unhatched blastocyst by scTrio-seq will help with uncovering the mystery of cell fate decision during human pre-implantation development and provide the database for improving the precision of pre-implantation genetic screening(PGS) in assisted reproduction technology(ART).

哺乳动物早期胚胎中细胞命运决定机制一直是生殖领域的研究热点。目前已知，在小鼠早期胚胎的四细胞阶段，卵裂球的异质性已表现在一些核心转录因子如Sox21的表达水平上。但在人类早期胚胎中卵裂球的异质性尚缺乏研究。.基于我们已完成的人类早期胚胎组学分析，本研究将针对从八细胞胚胎到早期囊胚这一发育过程，采用单细胞三重组学测序技术对完整胚胎的单卵裂球的转录组、基因组、表观组信息同时进行捕获。通过比较不同时间点、同一胚胎中各个卵裂球之间基因表达和甲基化修饰的差异，明确卵裂球出现异质性的时间点和特征，从而尝试寻找人类胚胎中参与调控卵裂球细胞命运的关键转录因子和表观遗传特征。.在人类早期胚胎发育的关键时间段内，利用单细胞测序技术追踪胚胎内部单卵裂球之间的异质性，将使揭开人类早期胚胎中细胞命运决定机制的神秘面纱成为可能，并为优化辅助生殖技术中植入前遗传筛查的标准提供数据支持。

利用单细胞三重组学测序（scTrio-seq）技术，以不同时间点、同一胚胎中各个卵裂球为研究对象，通过对单个卵裂球及单个胚胎的转录组、基因组、表观组信息同时进行捕获，研究比较不同时间点、同一胚胎中各个卵裂球之间基因表达和甲基化修饰的差异，明确卵裂球出现异质性的时间点和特征，追踪配子受精后胚胎的表观遗传的传递/动态变化情况。通过加权基因共表达网络WGCNA、KEGG系统功能互作网络等生物信息学技术分析早期胚胎发育中的序贯变化，挖掘患者早期胚胎发育的关键基因、调控元件及差异甲基化位点，寻找人类胚胎中参与调控卵裂球细胞命运的关键转录因子和表观遗传特征，建立早期胚胎的细胞编程及重编程基因调控标准。