基于染色体空间互作数据研究抑制性组蛋白修饰的转录负调控及其在细胞分化中的作用

H3K9me3 and H3K27me3 in promoter are reported to be implicated in transcription repression. Nevertheless, negative regulation of H3K9me3 and H3K27me3 on genes stayed the linear level with short physical distance. Meanwhile, spatial proximity plays important roles in transcription of genes. In previous researches, loop structures frequently occur between active regions. In reality, the percentages of interaction between promoters and repressive modifications is comparative with active regions. In our current study, we found that H3K9me3 spatially downregulates the transcription of genes in hESC, while H3K27me3 correlates with low expression in IMR90. On the base of that, we aim to testify that the spatial regulation of repressive modifications has additive effect in each functional cell. Linear proximity has been known to restrain transcription, so we want to compare effect of spatial proximity with linear proximity. To seek out target, whether they prefer to specific repeat sequence remains to be unknown. Then, GO analysis of genes downregulated by H3K9me3 and H3K27me3 in space will be performed, to probe the biological processes that repressive modifications are involved in. Finally, CRISPR technology knockouts modification region to disrupt the loop structure and damage the regulation, on the condition of not affecting the promoter. The upregulation of transcription contributes to verifying the spatial regulation of H3K9me3 and H3K27me3. Meanwhile, to explore the spatial function of modifications in cell differentiation process.

位于启动子区的H3K9me3和H3K27me3与转录抑制密不可分，然而它们对基因的负调控仅仅停留在线性的水平，即通过物理距离的靠近来抑制基因的转录。最近几年发现在细胞核内DNA通过空间环状结构接触在转录调控中起着重要的作用，并且倾向于发生在活性的区域。事实上，与活性区域增强子相比，抑制性组蛋白修饰也有一个相当的百分比参与空间相互作用。我们的前期研究表明，H3K9me3和H3K27me3分别在干细胞和IMR90中能通过空间相互作用下调基因的转录，本项目通过比较抑制性修饰在线性和空间上影响的大小量化空间调控；寻找这些修饰的空间靶位点的序列motif，推测其对基因组进化的压力；功能性聚类分析获悉空间参与调控的生物过程。同时将本课题涉及的高通量测序数据分析流程整合到数据库平台，构建数据分析平台；最后运用CRISPR技术进一步证明抑制性修饰在空间上的转录调控作用并探索其在细胞分化过程中的意义。

位于启动子区的H3K9me3和H3K27me3与转录抑制密不可分，然而它们对基因的负调控仅仅.停留在线性的水平，即通过物理距离的靠近来抑制基因的转录。最近几年发现在细胞核内DNA.通过空间环状结构接触在转录调控中起着重要的作用，并且倾向于发生在活性的区域。事实上.，与活性区域增强子相比，抑制性组蛋白修饰也有一个相当的百分比参与空间相互作用。我们.的前期研究表明，H3K9me3和H3K27me3分别在干细胞和IMR90中能通过空间相互作用下调基因的.转录，本项目通过比较抑制性修饰在线性和空间上影响的大小量化空间调控；寻找这些修饰的.空间靶位点的序列motif，推测其对基因组进化的压力；功能性聚类分析获悉空间参与调控的.生物过程。同时将本课题涉及的高通量测序数据分析流程整合到数据库平台，构建数据分析平.台；最后运用CRISPR技术进一步证明抑制性修饰在空间上的转录调控作用并探索其在细胞分化.过程中的意义。