Transcriptional regulation of gliogenesis in the CNS

描述（由申请人提供）：神经胶质细胞占成人中枢神经系统（CNS）细胞组成的约80%，并支持CNS功能所必需的大量生理作用，包括髓鞘形成、突触形成、神经传递和血脑屏障的形成。最近的胶质细胞发育研究已经证明了许多控制星形胶质细胞和少突胶质细胞亚系终末分化和成熟的机制。然而，我们的知识，以前的分子过程，控制启动胶质细胞从多能神经干细胞在体内仍然是基本的。这个建议的首要目标是阐明的分子机制，管理胶质细胞发生的启动。最近，我们发现Sox 9/NFIA关系代表了神经干细胞向胶质细胞谱系定向分化过程中的关键调控节点，因此，对其上游调控事件和下游转录网络的解剖将为控制胶质细胞生成的调控过程提供新的见解。 我们对胶质细胞发生中上游调控事件的初步研究表明，Sox 9和Brn 2通过不同的增强子元件共同调控NFIA，这些元件由Med 12介导的染色质循环聚集在一起。因此，在特定的aim 1中，我们将描述Brn 2如何调节NFIA表达以及Sox 9/Brn 2是否协同调节NFIA诱导和胶质细胞生成。在特定的aim 2中，我们将进行染色质构象捕获（3C），以确定NFIA基因座的三维结构，并检查染色质循环因子Med 12是否调节NFIA基因座的染色质构型，并与Sox 9/Brn 2合作调节NFIA诱导。为了鉴定关键的下游事件，我们将ChIP-Seq和FACS分离的CD 15+脊髓祖细胞上的基因表达谱分析相结合，以分离胶质细胞生成期间的Sox 9/NFIA转录网络。在特定的aim 3中，我们将验证和功能分析在该筛选中鉴定的一组候选胶质细胞生成靶点，并结合我们在胶质细胞生成期间的研究，将我们的ChIP-Seq分析扩展到早期发育阶段，以鉴定神经干细胞群体中的Sox 9特异性靶点

DESCRIPTION (provided by applicant): Glial cells comprise approximately 80% of the cellular constituency of the adult central nervous system (CNS) and support a vast array of physiological roles essential to CNS function, including myelination, synapse formation, neurotransmission, and formation of the blood-brain barrier. Recent studies of glial development have documented many of the mechanisms that control the terminal differentiation and maturation of the astrocyte and oligodendrocyte sublineages. However, our knowledge of the preceding molecular processes that control the initiation of gliogenesis from multipotent neural stem cells in vivo remains rudimentary. The overriding goal of this proposal is to elucidate the molecular mechanisms that govern the initiation of gliogenesis. Recently we found that the Sox9/NFIA relationship represents a crucial regulatory node during neural stem cell commitment to the glial lineage, therefore dissection of their upstream regulatory events and downstream transcriptional networks will provide novel insight into the regulatory processes that control earl gliogenesis. Our preliminary studies on the upstream regulatory events in gliogenesis suggest that Sox9 and Brn2 co-regulate NFIA through distinct enhancer elements that are brought together by Med12 mediated chromatin looping. Therefore in specific aim1 we will delineate how Brn2 regulates NFIA expression and whether Sox9/Brn2 collaboratively regulate NFIA induction and gliogenesis. In specific aim2, we will perform chromatin conformation capture (3C) to determine the three-dimensional architecture of the NFIA locus and examine whether the chromatin looping factor, Med12, regulates chromatin configuration at the NFIA locus and collaborates with Sox9/Brn2 to regulate NFIA induction. To identify key downstream events, we combined ChIP-Seq and gene expression profiling on FACS isolated, CD15+ spinal cord progenitors to dissociate the Sox9/NFIA transcriptional networks during gliogenesis. In specific aim3, we will validate and functionally analyze a set of candidate gliogenic targets identified in this screen and, in conjunction with our studies during gliogenesis, extend our ChIP-Seq analysis to earlier developmental stages to identify Sox9-specific targets in neural stem cell populations