Mechanisms governing Nuclear Factor I gene induction and function during the ini

初始阶段控制核因子 I 基因诱导和功能的机制

• 批准号: 7943766
• 负责人: Benjamin Deneen
• 金额: $ 34.23万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7943766
• 关键词: Action Potentials; Adult; Astrocytes; Astrocytoma; Blood - brain barrier anatomy; Central Nervous System Diseases; Coupled; Data; Developmental Process; Disease; Dissection; Elements; Embryo; Enhancers; Event; Gene Expression; Gene Expression Regulation; Gene Family; Gene Targeting; Generations; Genes; Genetic; Genetic Enhancer Element; Goals; Health; Indium; Knowledge; Lifting; Link; Malignant Neoplasms; Maps; Molecular; Mus; NFIA gene; Nervous System Physiology; Neuraxis; Neurodegenerative Disorders; Neuroglia; Oligodendroglia; Pathway interactions; Pattern; Physiological; Process; Property; Regulation; Response Elements; Role; Screening procedure; Series; Signal Pathway; Signal Transduction; Site; Specific qualifier value; Spinal Cord; Staging; Stress; Therapeutic Intervention; Transcriptional Activation; Transcriptional Regulation; base; bone morphogenic protein; clinical application; cohort; gain of function; gene induction; glial cell development; gliogenesis; in vivo; insight; loss of function; mutant; nerve stem cell; nervous system development; novel; novel therapeutic intervention; nuclear factor 1; prevent; programs; promoter; public health relevance; response; stem cell population; synaptogenesis; tool; transcription factor

DESCRIPTION (provided by applicant): Glial cells comprise approximately 90% of the cellular constituency of the adult central nervous system (CNS) and support a vast array of physiological roles essential to CNS function. Yet, the molecular processes that control the initiation of gliogenesis from multipotent neural stem cells in vivo remain poorly understood. Thus, the overriding goal of this proposal is to elucidate the mechanisms that govern the initiation of gliogenesis from neural stem cells. We recently demonstrated that nuclear factor I (NFI) genes control the generation of glial cells in the embryonic spinal cord and are induced in neural stem cell populations coincident with the onset of gliogenesis in vivo. These properties make the NFI genes an ideal starting point from which to investigate the genetic regulatory programs that induce and maintain the early stages of gliogenesis. We, therefore, hypothesize that dissection of both the upstream and downstream events associated with NFI gene regulation will provide novel insights into the molecular control of gliogenesis. Specific Aims 1 and 2 of this proposal are based on our discovery of two distinct regulators of NFI gene expression in the embryonic spinal cord. Using enhancer screening of the NFIA promoter we have identified a highly conserved enhancer element (e123) that recapitulates the spatial and temporal patterns of NFIA induction when introduced into the embryonic chick spinal cord. Thus, in Aim 1 we propose to exploit e123 as a tool to identify a core set of transcription factors that control NFIA induction. We have also found that bone morphogenic protein (BMP) signaling controls NFI gene expression in the embryonic spinal cord in a manner that is independent of the e123 enhancer studied in Aim 1. Therefore, in Aim 2 we plan to identify BMP-responsive elements in the NFIA promoter, define the specific role of BMP signaling in the regulation of NFI gene expression, and to establish that BMP signaling does indeed operate independently of the transcriptional control mechanisms that regulate e123 induction. Finally, Aim 3 is a logical extension of temporal profiling studies of gene expression in neural stem cells in which we identified a cohort of genes upregulated after NFI gene induction in the embryonic spinal cord. Preliminary studies indicate that four of these genes are sufficient to restore gliogenesis in the absence of NFIA, suggesting that they function downstream of NFI genes. We will use gain- and loss-of function approaches in vivo to discover whether and how these genes promote gliogenesis and function downstream of NFI genes during the initiation of gliogenesis. Upon completion of these studies, we expect to have a much more comprehensive map of molecular processes, both upstream and downstream of NFI genes that control the initiation of gliogenesis during CNS development. The resultant insights into the signals that specify commitment to the glial lineage should lift understanding of glial cell specification in the embryonic spinal cord from the speculative realm to a point where clinical applications can begin to be considered. PUBLIC HEALTH RELEVANCE: This project focuses on the molecular processes that control the generation of glial cells. Glial cells have been implicated in a vast array of cancers and degenerative diseases of the nervous system and understanding the developmental processes that control their generation is a key to developing new therapeutic approaches to these disorders. This proposal is centered around a gene family that controls the generation of glial cells and is also expressed in astrocytomas and contributes to their formation. Thus, the studies herein are directly applicable to the understanding and treatment of astrocytomas.

描述（由申请人提供）：神经胶质细胞约占成人中枢神经系统（CNS）细胞成分的 90%，并支持对 CNS 功能至关重要的大量生理作用。然而，控制体内多能神经干细胞胶质生成起始的分子过程仍然知之甚少。因此，该提案的首要目标是阐明控制神经干细胞胶质生成起始的机制。我们最近证明，核因子 I (NFI) 基因控制胚胎脊髓中神经胶质细胞的生成，并在神经干细胞群中被诱导，与体内神经胶质细胞生成的开始一致。这些特性使 NFI 基因成为研究诱导和维持胶质生成早期阶段的基因调控程序的理想起点。因此，我们假设对与 NFI 基因调控相关的上游和下游事件的剖析将为胶质细胞生成的分子控制提供新的见解。 该提案的具体目标 1 和 2 基于我们对胚胎脊髓中 NFI 基因表达的两个不同调节因子的发现。通过对 NFIA 启动子进行增强子筛选，我们鉴定了一个高度保守的增强子元件 (e123)，该元件概括了导入雏鸡脊髓时 NFIA 诱导的空间和时间模式。因此，在目标 1 中，我们建议利用 e123 作为工具来识别控制 NFIA 诱导的一组核心转录因子。我们还发现，骨形态发生蛋白（BMP）信号传导以独立于目标1中研究的e123增强子的方式控制胚胎脊髓中的NFI基因表达。因此，在目标2中，我们计划鉴定NFIA启动子中的BMP反应元件，定义BMP信号传导在调节NFI基因表达中的具体作用，并确定BMP信号传导确实 其运作独立于调节 e123 诱导的转录控制机制。最后，目标 3 是神经干细胞基因表达时间分析研究的逻辑延伸，其中我们鉴定了胚胎脊髓中 NFI 基因诱导后上调的一组基因。初步研究表明，其中四个基因足以在 NFIA 缺失的情况下恢复神经胶质生成，表明它们在 NFI 基因的下游发挥作用。我们将使用体内功能获得和丧失的方法来发现这些基因是否以及如何促进胶质细胞生成以及在胶质细胞生成起始过程中 NFI 基因下游的功能。完成这些研究后，我们期望获得更全面的分子过程图谱，包括 NFI 基因的上游和下游，这些基因控制中枢神经系统发育过程中胶质细胞生成的起始。由此产生的对指定神经胶质谱系信号的见解应该将胚胎脊髓中神经胶质细胞规范的理解从推测领域提升到可以开始考虑临床应用的程度。 公共健康相关性：该项目重点关注控制神经胶质细胞生成的分子过程。神经胶质细胞与多种癌症和神经系统退行性疾病有关，了解控制其生成的发育过程是开发治疗这些疾病的新方法的关键。该提议以控制神经胶质细胞生成的基因家族为中心，该基因家族也在星形细胞瘤中表达并有助于其形成。因此，本文的研究可直接应用于星形细胞瘤的理解和治疗。