LincRNA GAS5在胚胎干细胞和体细胞细胞周期调控中的不同作用及其机制研究

胚胎干细胞(ESC)有着独特的增殖能力，但是ESC中是否存在与体细胞不同的细胞周期调控机制尚未阐明。我们近期通过人ESC全转录组测序研究发现，长链非编码RNA GAS5与人ESC自我更新高度相关，并可以加快ESC细胞周期和增殖；而文献中GAS5却可以通过糖皮质激素受体（GR）抑制多种体细胞的增殖。为什么GAS5在ESC和体细胞中的作用完全相反？针对这一问题，我们拟首先分别在ESC和体细胞中对比分析GAS5对细胞增殖和细胞周期的调控作用；随后在机制研究中，一方面通过ESC与体细胞中GR活性的对比研究，分析GAS5/GR通路是否参与ESC增殖，一方面通过RNA表达改变和RNA竞争性结合研究，分析GAS5是否作为microRNA海绵抑制ESC特异性microRNA和调控细胞周期蛋白。最终阐明GAS5在人ESC和体细胞中发挥不同功能的机制，从而更好地认识非编码RNA在干细胞特异性调控网络中的作用。

What are the differences between the mechanism of embryonic stem cells (ESC) maintaining and self-renewal in vitro and the somatic cell proliferation, is a critical question to understand the characteristics of stem cells, explore the mechanism of cell aging, and understand the cell reprogramming. In our previous research basing on whole transcriptome sequencing of human ESC, we found a long non coding RNA GAS5 is highly related with human ESC self-renewal, and can promote stem cell in vitro amplification process. But， which is interesting, the GAS5 in human somatic cells is to inhibit cell proliferation through supressing the glucocorticoid receptor (GR) activity. To reveal the underlying mechanism of this phenomenon, we will first study the role of GAS5 on ESCs maintaining and self-renewal through the overexpression and knock-out ESCs in the in vivo and in vitro experiments with HEK293 cells as controls; furthermore exclude the role of GR-related regulation for GAS5 in human ESC through the analysis of GR expression and activity; and then validate whether GAS5 can play as a microRNA sponge to regulate stem-cell-specific microRNAs according to the RNA expression analysis, bioinformatics prediction, target validation and RISC-RNA interaction analysis. Our goal is to validate the different functions of GAS5 in the cell cycle regulations of ESCs and somatic cells and reveal its underlying mechanisms, and then provide better understanding to the role and mechanism of long non-coding RNA in the stem-cell-specific molecular regulatory network.