多能干细胞特异的逆转座子缺失：发生机制和对基因表达影响的组学研究

项目名称： 多能干细胞特异的逆转座子缺失：发生机制和对基因表达影响的组学研究

项目编号： No.31501020

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 生物科学

项目作者： 郑彩宏

作者单位： 中国科学院北京基因组研究所

项目金额： 22万元

中文摘要： 逆转座子是真核基因组中的重要组成部分，部分逆转座子的转录本参与了哺乳动物早期胚胎发育和干细胞的多能性维持。逆转座子也可插入整合到调控区域，行使顺式调控作用，调节目标区域内基因的表达。我们先前的研究发现，小鼠多能干细胞，相对于分化细胞，在部分细胞中存在特异的逆转座子缺失，造成多能干细胞的遗传异质性，并且这些缺失与分化状态相关。本项目基于先前的研究发现，从如下两个方面展开后续研究：（1）通过断点处序列基序和表观基因组分析，解析此类逆转座子缺失与重组热点、逆转座子活性及染色质结构的相关性，并通过RNAi实验进一步确立染色质结构的改变对缺失发生的影响，从而揭示缺失发生的潜在机制；（2）通过单细胞整合分析技术，解析逆转座子缺失对相关基因表达的影响，从而探究其在多能干细胞表达异质性和多能性维持中作用。期望通过以上研究，揭示多能干细胞中逆转座子缺失的发生机制和生物学功能。

中文关键词： 逆转座子缺失；多能干细胞；单细胞整合分析；基因组学；差异表达基因

英文摘要： Retrotransponson is an essential component in eukaryotic genomes. Transcripts of certain retrotransposons involve in the process underlying early embryonic development and pluripotency maintenance of stem cells in mammals. In addition, retrotransposon is recruited in regulating of gene expression via playing a cis-acting role by its integration into the genome. Unexpectedly, a set of retrotransposons was detected in our recent findings, which specifically and precisely deleted in parts of mouse induced pluripotent stem cells compared with the parental somatic cells, meanwhile introduced a genetic heterogeneity. Experimental evidence indicated the occurrence of such retrotransposon deletions is associated with pluripotency. However, the mechanism of these unique deletions of retrotransposons and the subsequent effects in pluripotent stem cells are unknown. We attempt to propose a research plan including the following two sections: (1) To evaluate the recombination hotspots and epigenomic factors such as DNA methylation and chromatin structure that might lead to the occurrence of deletions of retrotransposons via a association study and RNAi experiments. (2) Via integrated analysis of genome and transcriptome of one single cell, to evaluate the impacts of deletions of retrotransposon on transcriptome in each cell, and thereby to explore the corresponding functions in maintenance of transcriptional heterogeneity and pluripotency in pluripotent stem cells. Through the studies in this plan, we expect to reveal the potential mechanism and biological function of the unique deletions of retrotransposons in pluripotent stem cells.

英文关键词： deletion of retrotransponson ;pluripotent stem cell;integrated single-cell analysis;genomics;differentially expressed genes