Cajal body重构染色质三维结构促进肝癌发生的作用和机制研究

基因的正确表达调控需要在染色质折叠成的复杂三维结构中完成。肿瘤发生过程中染色质结构变化与基因表达的关系还十分不清。我们前期研究发现，细胞核体Cajal bodies（CBs）与组蛋白、核小分子RNA区域高度相关，形成独特三维非随机结构，调节肿瘤相关基因表达。肝癌细胞高表达CBs，下调CBs导致组蛋白基因簇HIST1三维互作破坏及表达降低。CBs在原代细胞不表达，但原癌基因可快速促进CBs产生，并引起HIST1空间位置改变及转录激活。本项目拟构建肝细胞原癌基因诱导表达动态模型，结合CRISPR/Cas9 基因编辑、DNA-FISH、高通量染色质构象捕获Hi-C 、RNA-seq和Chip-seq 等技术研究CBs在肿瘤发生中的作用，从全新的角度阐明CBs通过重构染色质三维结构调节基因表达，促进肝癌发生。本项目将为临床预防和控制肝癌提供新的分子靶点，也为细胞核体研究提供新的理论依据。

The dynamic and complex three-dimensional genomic interactions in the nucleus exert critical roles in regulated gene expression. We do not yet understand the changes in nuclear and genomic organization that lead to cancer transformation and progression. Recently Cajal bodies have been found to be associated frequently with histone and small nuclear RNA locus and they are formed into a unique three-dimensional non-random positioning to regulate tumor-related gene expression. Our previous study found that CBs are highly expressed in hepatoma carcinoma cells (HCC). Disassembly of CBs suppressed the expressions of histone HIST1 gene cluster, which play an essential role in maintaining HCCs function. CBs normally are absent in healthy primary cells but appear rapidly and universally after cancer gene transformation, which suggest that CB might be an early event of tumorigenesis. We propose to use inducible CB formation model system in Primary hepatocytes to examine the dynamic reorganization of nuclear architecture during cancer gene transformation. By using CRISPR/Cas9, DNA FISH, high-throughput chromosome conformation capture Hi-C, RNA-seq and GoldCLIP, we aims to study the function and significance of Cajal bodies in the process of proto-oncogene transformation of hepatocellular carcinoma cells. We will provide new evidence for the study of nuclear bodies.