长链非编码RNA调控大脑皮层神经干细胞分化的分子机制

In the human and mouse cerebral cortex, differentiation of neural stem cells relies on precise gene expression regulation. In the mammalian genome, a small portion encodes protein coding genes. The majority of transcripts is noncoding RNAs, in particular long noncoding RNAs (lncRNAs). Many lncRNAs are expressed in neural stem cells. However, little is known about their functions. In our preliminary studies we have screened a lncRNA Sox2ot that is highly expressed in the mouse embryonic cortex, and we have found it to promote differentiation of neural stem cells. In this proposal, we attempt to address a fundamental question of how lncRNAs cooperate with neighbor coding genes in order to control neurogenesis in developing cortices. We will first reveal the role of Sox2ot in regulating development of neural stem cells and neural progenitors. We will next examine the molecular mechanism of interactions between Sox2ot and its neighbor coding gene Sox2 in the mouse genome. We will further screen and test the role of specific Sox2ot transcript variants that are highly expressed in neural stem cells. The success of this project will provide crucial guidelines and technical supports for further investigating functions of lncRNAs, and understanding lncRNA-mediated regulation of neurological diseases.

人类和小鼠大脑发育过程中，大脑皮层神经干细胞和神经祖细胞的分化受到精确的基因表达调控。哺乳动物基因组中，蛋白质编码基因只占很少的一部分，大部分转录本是非编码RNA，尤其是长链非编码RNA（lncRNA）。一些lncRNA在大脑神经干细胞中表达，我们对它们的功能和作用机理了解很少。我们的前期研究筛选到lncRNA—Sox2ot在小鼠胚胎大脑皮层表达，并发现Sox2ot促进神经干细胞分化。本课题拟解决的关键问题是：研究Sox2ot与基因组中邻近的编码基因，协同调控大脑皮层神经发生的分子机制。本课题中，我们首先分析Sox2ot控制大脑皮层神经干细胞、祖细胞发育的生物学功能；然后阐述Sox2ot和编码基因Sox2作用的分子机制；最后筛选并研究在神经干细胞中特异高表达的Sox2ot转录变异体的功能和机理。本课题为探索lncRNA的功能，以及它们在神经系统疾病中的作用，提供坚实的理论基础和技术支持。

本课题的研究目标是分析一个长链非编码RNA—Sox2ot与它的邻近编码基因Sox2相互作用，共同调控大脑皮层神经干细胞分化和神经发生的分子机理。我们的项目取得了以下主要进展和发现：1）lncRNA中Sox2ot在小鼠胚胎大脑发育中，主要功能是促进神经元的生成。2）Sox2ot与Sox2拮抗，造成神经祖细胞数量减少，分化增多。3）YY1会抑制大脑皮层神经干细胞、祖细胞的扩增，并诱导分化。4）YY1是Sox2的转录抑制因子，在神经干细胞中过表达YY1后，Sox2的转录水平和蛋白水平会相应下降。5）lncRNA同样会被甲基化调控，并筛选了在大脑皮层神经祖细胞及分化神经元中，被甲基化的lncRNA。本项目为研究lncRNA调控大脑发育的分子机制及大脑发育异常的分子检测提供可靠的科研依据，为开发长链非编码RNA作为神经系统疾病诊断和治疗的分子靶标奠定理论基础。