Epigenomic Profile and Function of H3.3 Variant During Sensitive Period of Neurod

描述（申请人提供）：神经发育是一个复杂的动态过程，涉及基因与环境的相互作用，导致基因表达、细胞功能、电路形成、神经元形态和行为的一系列变化。表观遗传和基于染色质的修饰介导不同的细胞基因表达谱，而不直接影响DNA序列，以响应环境刺激。令人兴奋的新研究表明，除了核小体重塑和共价组蛋白修饰外，真核细胞还通过引入变异组蛋白来产生染色质结构的变化。新出现的证据表明，H3.3是一个理想的染色质标记，可以有效地分析转录维持和调控关键时期表观基因组景观的动态变化。因此，我们将探索H3.3特异性变异定位与神经发育纵向阶段基因表达的后续下游模式之间的潜在新联系。我们的中心假设是，在神经发育的关键时期经历的环境刺激与组织特异性H3.3沉积谱的强烈变化有关，因此，对H3.3表观基因组的全面纵向分析有望为早期环境影响对成年期精神障碍易感性变化的影响提供根本性的新见解。我们试图在以下三个相互关联的特定目标中验证这一工作假设：1)在整个神经发育过程中确定组蛋白H3.3在大脑中的纵向定位模式。我们的目标是在标准基础条件下，使用标记的H3.3敲入小鼠或特定的H3.3抗体，对发育和成年大脑中的组蛋白H3.3变异定位进行无偏倚的表观基因组（ChIP-seq）分析，特别强调位于边缘回路内的大脑区域（例如海马和皮层）。2)研究早期生活经历对大脑组蛋白H3.3调控和再定位的影响。我们的目的是研究早期生活环境富集对H3.3沉积在整个染色质模板中的定向能力，从而影响发育基因调控的正常模式。3)通过调控的功能丧失和功能获得研究确定H3.3沉积的功能相关性。我们的目标是生成互补的小鼠品系和工具进行研究，并对这些动物进行实验，以探索H3.3变异沉积在指导受发育影响的认知和社会行为中的生物学作用。总的来说，我们的研究将为神经发育过程中的表观基因组提供新颖而关键的信息。识别表观遗传状态改变的基因和基因网络将有助于更好地描述大脑发育敏感时期的“表观遗传景观”，并为与精神障碍相关的治疗干预找到新的靶点。

DESCRIPTION (provided by applicant): Neurodevelopment is an intricate and dynamic process involving gene-environment interactions, which result in a series of changes in gene expression, cellular function, circuit formation, neuronal morphology and behavior. Epigenetic and chromatin-based modifications mediate distinct cellular gene expression profiles in vivo without directly affecting the DNA sequence in response to environmental stimuli. Exciting new research indicates that in addition to nucleosomal remodeling and covalent histone modifications, eukaryotic cells generate variation in chromatin structure through the introduction of variant histone proteins. Emerging evidence indicates that H3.3 represents an ideal chromatin mark for efficiently profiling dynamic changes in the epigenomic landscape during critical periods of transcriptional maintenance and regulation. We therefore will explore potential novel links between H3.3 specific variant localization and subsequent downstream patterns of gene expression during longitudinal stages of neurodevelopment. Our central hypothesis is that -- environmental stimuli experienced during critical periods of neurodevelopment are associated with robust changes in tissue specific H3.3 deposition profiles, such that comprehensive longitudinal analyses of the H3.3 epigenome promise to provide fundamentally novel insight into the impact of early environmental influences on the development of altered vulnerabilities to mental disorders during adulthood. We seek to test this working hypothesis in the following three interrelated Specific Aims: 1) Identify longitudinal histone H3.3 localization patterns in brain throughout neurodevelopment. We aim to perform unbiased epigenome-wide (ChIP-seq) analyses of histone H3.3 variant localization in the developing and adult brain, with specific emphasis on brain regions located within the limbic circuitry (e.g. hippocampus and cortex), using tagged H3.3 knock-in mice or a specific H3.3 antibody under standard basal conditions. 2) Examine the impact of early life experiences on histone H3.3 regulation and relocalization in brain. We aim to examine the ability of early life environmental enrichment to redirect H3.3 deposition throughout the chromatin template, thereby influencing normal patterns of developmental gene regulation. 3) Determine the functional relevance of H3.3 deposition by means of regulated loss-of-function and gain-of-function studies. We aim to generate complementary mouse lines and tools to study, and conduct experiments with these animals to explore the biological role of H3.3 variant deposition in guiding developmentally influenced cognitive and social behaviors. Collectively our studies will provide novel and critical information regarding the epigenome across neurodevelopment. Identification of genes and gene networks with altered epigenetic status will help to better describe the "epigenetic landscape" during sensitive periods of brain development and pinpoint novel targets for therapeutic intervention related to mental disorders.