小鼠早期胚胎发育过程中组蛋白H3K4me3修饰长度变化的调控机制及其作用

在植入前胚胎发育过程中，组蛋白修饰对基因的表达起着很重要的调控作用。但是由于细胞数量的限制，对植入前胚胎的组蛋白修饰研究还很有限。利用申请人建立的微量细胞ChIP-seq技术，我们对植入前胚胎的组蛋白修饰进行了全基因组水平的检测，结果发现，在小鼠植入前胚胎发育过程中，组蛋白H3K4me3修饰的长度发生了剧烈的变化，这些长度的变化与基因的表达水平密切相关。干扰相关酶的表达会导致H3K4me3修饰的长度异常，胚胎会在植入前的发育过程中死亡。这些结果都表明H3K4me3修饰的长度在小鼠植入前胚胎发育过程中起了很重要的作用。在本项目中，我们将对小鼠胚胎中H3K4me3修饰的长度的调控机制及其作用进行研究，通过RNA干扰的方式筛选调控H3K4me3修饰的长度变化相关的酶，并利用CRISPR-Cas9技术构建相应基因的敲除小鼠，以阐明H3K4me3修饰长度变化在胚胎发育过程中的作用和调控机制。

Histone modifications have critical roles in regulating the expression of developmental genes during embryo development in mammals . However, genome-wide analyses of histone modifications in pre-implantation embryos remain unclear because of the limited number of cells. We have established a small scale chromatin immunoprecipitation followed by sequencing (ChIP–seq) method and mapped the genome-wide profiles of H3K4me3 and H3K27me3 in mouse pre-implantation embryos. We found the breadth of the H3K4me3 domain is a highly dynamic feature, and associated with gene expression level. Knockdown of H3K4me3 demethylase widened the H3K4me3 domains at the morula stage and caused unsuccessful lineage differentiation.These results indicated that the dynamic of H3K4me3 length play an important role in pre-implantation embryos. In this project, we intend to screen the enzymes which are responsible for the dynamic of H3K4me3 length by RNA interference in mouse early embryos. Moreover, using the CRISPR-Cas9 system, we will generate the knockout mice of key enzymes to .investigate the mechanism and function of the dynamic of H3K4me3 signal length in mouse pre- and post-implantation embryos.