Chromatin Mechanisms of Neuronal Maturation

神经元成熟的染色质机制

• 批准号: 9929776
• 负责人: Anne Elizabeth West
• 金额: $ 5.66万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9929776
• 关键词: ARHGEF5 gene; Address; Adult; Biological Models; Brain; CRISPR/Cas technology; Cells; Cerebellum; ChIP-seq; Chromatin; Chromatin Structure; Cues; Cytoplasmic Granules; Data; Development; Distal; Enhancers; Enzymes; Event; Foundations; Gene Activation; Gene Expression; Gene Silencing; Genes; Genetic Transcription; Genomic DNA; Genomics; Goals; Histone H3; Histones; Impairment; Intellectual functioning disability; Kinetics; Knock-out; Lysine; Mediating; Modification; Molecular; Mus; Mutation; Neurodevelopmental Disorder; Neuronal Differentiation; Neurons; Phase; Phosphorylation; Play; Population; Process; Proteins; Recruitment Activity; Regulation; Regulator Genes; Regulatory Element; Repression; Role; Sensory; Synapses; Testing; Time; Transcriptional Activation; Transcriptional Regulation; Variant; autism spectrum disorder; cell type; critical period; demethylation; derepression; epigenetic regulation; experimental study; gene induction; gene product; histone methyltransferase; in vivo; insight; knock-down; mRNA Expression; mouse model; neuronal circuitry; parent grant; postnatal; programs; promoter; relating to nervous system; selective expression; synaptic function

PROJECT SUMMARY Neuronal differentiation requires the precise orchestration of gene expression programs. Temporal control of transcription is particularly important in maturing postmitotic neurons of the postnatal brain because these cells need to express gene products that refine neuronal function and circuitry during specific critical periods of brain development. Epigenetic regulation of chromatin structure is known to play a role in establishing cell-type specific programs of gene expression during early stages of cell fate determination, but the chromatin mechanisms that regulate gene expression during terminal phases of differentiation remain to be fully understood. The goal of this proposal is to identify chromatin mechanisms that coordinate the induction of genes in maturing neurons of the CNS. To discover these chromatin mechanisms of neuronal differentiation, and to determine how these mechanisms are regulated across multiple stages of neuronal maturation, we have characterized chromatin accessibility, enhancer activation, and gene expression in differentiating cerebellar granule neurons (CGNs) of the postnatal mouse in vivo. We have observed that thousands of regulatory elements show chromatin accessibility changes as CGNs differentiate, and we have verified that many of these differentially accessible regions function as developmental stage-specific enhancers of neuronal genes. Furthermore our data identify a specific group of the genes selectively expressed in mature CGNs of the cerebellum that are associated with repressive histone H3 lysine 27 trimethylation (H3K27me3) at early postmitotic stages of CGN differentiation yet lose this mark as CGNs mature. Consistent with a role for active histone demethylation in the induction of these genes, we find that at least a subset of these genes show increased H3K27me3 and reduced mRNA expression in CGNs lacking the H3K27 demethylase Kdm6b. The overarching hypothesis of this proposal is that the molecular regulators of H3K27me3 dynamics in postmitotic neurons play a key role in timing neuronal maturation. To address this hypothesis we propose the following Specific Aims: 1) To characterize the dynamic demethylation of H3K27 in postmitotic neurons maturing in vivo, 2) To determine the role of the H3K27 demethylase Kdm6b in neuronal maturation, and 3) To identify enhancer mechanisms of transcriptional derepression in maturing neurons. Together these studies will identify the molecular mechanisms that mediate the gene-specific loss of H3K27me3 in maturing CGNs, and they will directly test the importance of the developmental derepression of H3K27me3-silenced genes for functional neuronal maturation.

项目摘要 神经元分化需要基因表达程序的精确编排。时间上控制 转录在出生后脑的成熟的有丝分裂后神经元中是特别重要的， 需要表达基因产物，在大脑的特定关键时期改善神经元功能和电路 发展已知染色质结构的表观遗传调节在确定细胞类型中起作用。 在细胞命运决定的早期阶段，基因表达的特定程序，但染色质 在分化的终末阶段调节基因表达的机制仍然是完全不清楚的。 明白该提案的目标是确定协调诱导的染色质机制， 基因在中枢神经系统的成熟神经元中。为了发现神经元分化的这些染色质机制， 为了确定这些机制在神经元成熟的多个阶段中是如何调节的，我们 在分化过程中具有染色质可及性、增强子激活和基因表达的特征， 小脑颗粒神经元（CGN）的出生后小鼠体内。我们观察到， 调控元件显示，随着CGN分化，染色质可及性发生变化，我们已经证实， 这些差异可及区域中的许多作为神经元的发育阶段特异性增强子起作用。 基因.此外，我们的数据确定了一组特定的基因选择性表达在成熟的CGN， 小脑与早期抑制性组蛋白H3赖氨酸27三甲基化（H3K27me3）有关 CGN分化的有丝分裂后阶段随着CGN成熟而失去该标记。与活跃的角色一致 组蛋白去甲基化诱导这些基因，我们发现，至少这些基因的一个子集显示， 在缺乏H3K27去甲基化酶Kdm6b的CGN中增加H3K27me3并降低mRNA表达。的 该建议的首要假设是，H3K27me3动力学的分子调节剂在 有丝分裂后的神经元在神经元成熟的定时中起关键作用。为了解决这个假设，我们提出了 以下具体目的：1）表征H3K27在有丝分裂后神经元中的动态去甲基化 2）确定H3K27脱甲基酶Kdm6b在神经元成熟中的作用，和3） 鉴定成熟神经元中转录去抑制的增强子机制。这些研究将 鉴定在成熟CGN中介导H3K27me3基因特异性丢失的分子机制，和 他们将直接测试H3K27me3沉默基因的发育去阻遏对于 功能性神经元成熟