Epigenetic Maintenance of Neural Cell Identity

神经发育障碍(NDDS)包括一组遗传和表型不同的 通常以精神损害为特征的病理学。这些物质的分子基础 神经病理学仍然知之甚少。最近的全基因组测序研究表明 编码异染色质修饰物的基因突变与NDDS显著相关。这一类人 转录调节因子被认为通过实施可遗传的沉默来稳定神经细胞的身份和功能 通过表观遗传的染色质修饰的谱系非特定基因。然而，由于大多数异染色质 修饰物普遍表达，缺乏序列特异性，(1)抑制物的靶向有多精确 染色质是受控制的，以及(2)一般异染色质修饰物的突变如何导致NDD- 相关的神经元缺陷仍不清楚。为了在这些问题上获得实验上的吸引力，我们将检查 高度可信的新城疫风险基因ZNF462招募异染色质的机制 修饰EHMT1/2。我们将测试ZNF462是否以及如何限制谱系非特异性基因的表达 并维持神经细胞的特性。ZNF462单倍体功能不全导致Weiss-Kruszka综合征 NDD以神经发育缺陷为特征，包括发育迟缓和自闭症。然而， C2H2锌指蛋白在神经发育中的作用尚不清楚。我们之前发现老鼠 Zfp462是内皮基因抑制所必需的，它引导依赖Ehmt1/2的异染色质 神经前体细胞中转座元件(TE)衍生的增强子。我们假设人类ZNF462 通过特别限制非神经基因的表达来控制兼性异染色质的形成 神经发生。然而，我们预测，由于TES的快速物种进化，ZNF462将具有 新的人类靶点和控制一个独特的基因调控网络。因此，我们将：(目标1)使用神经 表观基因组和转录组偶联的人胚胎干细胞分化为 研究ZNF462杂合性对维持神经基因表达的影响，(目标2)执行 MESCs结构-功能分析和功能互补鉴定ZNF462蛋白结构域 负责同源二聚化、DNA结合和转录抑制以及(目标3)轮廓CTCF 神经上皮干细胞的结合和三维染色体构象研究 ZNF462杂合性对神经特异性基因组结构的影响。我们的建议提供了一条途径 对ZNF462依赖的基因沉默的分子机制的新见解，并增强我们的 对Weiss-Kruszka综合征病因的认识。以下战略将揭示以下新概念 基因调控和神经生物学，并阐明异染色质修饰物突变和 NDDS。总体而言，我们的工作将为预防和治疗表观遗传学引起的NDDS提供新的策略 监管失调。

Neurodevelopmental disorders (NDDs) comprise a group of genetically and phenotypically heterogeneous pathologies commonly characterized by psychiatric impairment. The molecular basis of these neuropathologies remains poorly understood. Recent whole-genome-sequencing studies revealed that mutations in genes encoding heterochromatin modifiers are significantly associated with NDDs. This class of transcriptional regulators is thought to stabilize neural cell identity and function by enforcing heritable silencing of lineage non-specific genes through epigenetic chromatin modifications. However, since most heterochromatin modifiers are ubiquitously expressed and lack sequence-specificity, (1) how precise targeting of repressive chromatin is controlled and (2) how mutations in general heterochromatin modifiers contribute to NDD- associated neuronal defects remains unclear. To gain experimental traction on these questions, we will examine the mechanism by which a high-confidence NDD risk gene, ZNF462, recruits the heterochromatin modifiers EHMT1/2. We will test whether and how ZNF462 restricts lineage non-specific gene expression and maintains neural cell identity. ZNF462 haploinsufficiency causes Weiss-Kruszka syndrome, a complex NDD characterized by neurodevelopmental defects including developmental delay and autism. However, the neurodevelopmental role of the C2H2 zinc finger protein is unknown. We previously discovered that mouse Zfp462, is required for endodermal gene repression, directing Ehmt1/2-dependent heterochromatin to transposable element (TE)-derived enhancers in neural progenitor cells. We hypothesize that human ZNF462 controls facultative heterochromatin formation, by specifically restricting non-neural gene expression during neurogenesis. However, we predict that due to rapid species-specific evolution of TEs, ZNF462 will have novel human targets and control a distinct gene regulatory network. W e will therefore: (Aim 1) employ neural differentiation of human embryonic stem cells (hESCs) coupled to epigenome and transcriptome profiling to investigate the impact of ZNF462 heterozygosity on maintenance of neural gene expression, (Aim 2) perform structure-function analysis and functional complementation in mESCs to identify ZNF462 protein domains responsible for homodimerization, DNA binding and transcriptional repression and (Aim 3) profile CTCF binding and three-dimensional chromosome conformation in neuroepithelial stem cells (NESCs) to investigate the impact of ZNF462 heterozygosity on neuro-specific genome architecture. Our proposal provides a path to novel insight into the molecular mechanism of ZNF462-dependent gene silencing, and enhance our understanding of the etiology of Weiss-Kruszka syndrome. The following strategy will reveal new concepts in gene regulation and neurobiology and elucidate the link between mutations in heterochromatin modifiers and NDDs. Overall, our work will inform novel strategies to prevent and treat NDDs arising from epigenetic dysregulation.