Roles of Gsx factors in basal ganglia development

Gsx 因子在基底神经节发育中的作用

基本信息

批准号：
10544505
负责人：
KENNETH J CAMPBELL
金额：
$ 62.37万
依托单位：
CINCINNATI CHILDRENS HOSP MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2026-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10544505
关键词：
Alleles Amino Acids Anatomic Models Anatomy Anterior Attention deficit hyperactivity disorder Basal Ganglia Behavioral Binding Binding Sites Biochemical Biochemistry Bioinformatics Biological Assay Brain Cell Culture Techniques Cell Nucleus Child Childhood Neurological Disorder Cognition Corpus striatum structure Coupled DNA DNA Binding DNA-Binding Proteins Data Data Analyses Data Set Development Disease Dorsal Dystonia Electrophoretic Mobility Shift Assay Elements Embryo Enhancers Exhibits Functional disorder Gene Activation Gene Expression Gene Expression Profiling Gene Expression Regulation Genes Genetic Genetic Enhancer Element Genetic Transcription Genomic approach Genomics Gilles de la Tourette syndrome Goals Grant Histologic Human Image In Vitro Intellectual functioning disability Intellectual impairment Interneurons Lateral Magnetic Resonance Imaging Maps Mediating Modeling Molecular Morphology Movement Mus Neurologic Symptoms Neuronal Differentiation Neurons Nonsense Codon Obsessive-Compulsive Disorder Outcome Pathologic Patients Pattern Phenotype Play Process Prosencephalon Protein Deficiency Publishing Regulation Regulator Genes Regulatory Element Reporter Repression Research Resolution Role Site Specific qualifier value Specificity Symptoms System Telencephalon Testing Transcriptional Regulation Variant Work behavioral phenotyping cell type dimer functional genomics gene repression genetic variant homeodomain human embryonic stem cell in vivo insight monomer mouse genetics mouse model mutant nerve stem cell neural circuit neural patterning neurogenesis novel olfactory bulb postnatal progenitor transcription factor transcriptome sequencing

项目摘要

Normal brain function relies on the correct assembly of neural circuits during development. This process starts with the patterning of neural progenitors along the dorsal-ventral and anterior-posterior axes to give rise to distinct subtypes of neurons. A number of key transcription factors (TFs) control the process of neuronal subtype specification. Work in the mouse has shown that the homeodomain (HD) TF Gsx2 plays essential roles in the patterning and differentiation of neuronal cell types that arise from progenitors in the lateral ganglionic eminence (LGE) of the embryonic mouse telencephalon. These progenitors give rise to cell types that include the striatal projection neurons of the basal ganglia and interneurons in the olfactory bulb, both of which are severely reduced in mouse Gsx2 mutants. Accordingly, human patient studies identified 2 pathological GSX2 variant alleles in children with serious neurological symptoms, including dystonia and intellectual disabilities. Consistent with these symptoms, MRI imaging revealed severe basal ganglia agenesis. One GSX2 variant results in a null allele, however, the other is a missense variant (Q251R) that alters a key amino acid in the DNA binding HD. We generated a mouse model of this human variant and our initial studies suggest that the Q>R variant leads to a strong embryonic LGE and basal ganglia phenotype that is morphologically similar to embryos with Gsx2 null alleles. Furthermore, our preliminary data indicate that this human HD variant alters Gsx2 DNA binding specificity, and thereby may account for the observed phenotypes. Moreover, we recently determined that Gsx2 binds and regulates target genes via two mechanisms; as a monomer Gsx2 represses gene expression whereas on a subset of DNA sites cooperative Gsx2 binding to dimer sites appears to facilitate gene expression. Intriguingly, the Dlx HD TFs, which lie downstream of Gsx2 during LGE progenitor maturation, also bind monomer sites but instead of repressing they activate gene expression. In this application, we propose to determine how Gsx2 and the Dlx TFs regulate LGE gene expression during basal ganglia development. To achieve this goal, we will test the following hypotheses in 3 independent specific aims: 1) To test the hypothesis that Gsx2 controls basal ganglia development by mediating distinct gene regulatory outcomes in a DNA binding site dependent manner. 2) To test the hypotheses that Gsx2 and Dlx TFs regulate a common set of LGE genes though direct competition for shared enhancer elements. 3) To test the hypothesis that the GSX2Q251R human variant causes altered DNA binding specificity, and thereby results in the mis-regulation of LGE gene expression and ultimately basal ganglia agenesis. Our approach will combine the use of mouse genetics and human forebrain neural stem cell cultures with molecular, biochemical, and genomic approaches to study transcriptional control of neuronal specification in the developing basal ganglia. The unique expertise of our research team at CCHMC allows us to take this broad approach, and thus increases our chances to gain a deeper understanding of how Gsx factors control basal ganglia development as well as to uncover new gene regulatory mechanisms that underlie dysfunction in certain childhood neurological disorders.

正常的大脑功能依赖于发育过程中神经回路的正确组装。这个过程开始于神经祖细胞沿着背腹轴和前后轴形成模式，产生不同的亚型神经元。许多关键转录因子 (TF) 控制神经元亚型规范的过程。工作于小鼠已证明同源域 (HD) TF Gsx2 在由胚胎小鼠外侧神经节隆起 (LGE) 祖细胞产生的神经元细胞类型端脑。这些祖细胞产生细胞类型，包括基底神经节的纹状体投射神经元和嗅球中的中间神经元，这两个神经元在小鼠 Gsx2 突变体中均严重减少。据此，人类患者研究在患有严重神经系统症状的儿童中发现了 2 个病理性 GSX2 变异等位基因，包括肌张力障碍和智力障碍。与这些症状一致，MRI 成像显示严重的基底神经节发育不全。一种 GSX2 变体导致无效等位基因，然而，另一种是错义变体 (Q251R)，它改变了一个关键 DNA结合HD中的氨基酸。我们生成了这种人类变体的小鼠模型，我们的初步研究表明 Q>R 变异导致强烈的胚胎 LGE 和基底神经节表型，其形态学上类似于具有 Gsx2 无效等位基因的胚胎。此外，我们的初步数据表明，这种人类 HD 变体改变了 Gsx2 DNA 结合特异性，从而可以解释观察到的表型。此外，我们最近确定 Gsx2 通过两种机制结合和调节靶基因；作为单体 Gsx2 抑制基因表达，而在子集上 DNA 位点协同 Gsx2 与二聚体位点的结合似乎促进了基因表达。有趣的是，Dlx HD 在 LGE 祖细胞成熟过程中位于 Gsx2 下游的 TF 也结合单体位点，但不是抑制它们激活基因表达。在此应用中，我们建议确定 Gsx2 和 Dlx TF 如何调节 LGE 基底神经节发育过程中的基因表达。为了实现这一目标，我们将在 3 年内检验以下假设独立的具体目标：1）检验 Gsx2 通过介导不同的信号来控制基底神经节发育的假设以 DNA 结合位点依赖方式产生基因调控结果。 2) 检验 Gsx2 和 Dlx TF 的假设通过直接竞争共享增强子元件来调节一组常见的 LGE 基因。 3）检验假设 GSX2Q251R 人类变体导致 DNA 结合特异性改变，从而导致错误调节 LGE 基因表达和最终基底神经节发育不全。我们的方法将结合小鼠遗传学和采用分子、生化和基因组方法培养人前脑神经干细胞来研究转录控制发育中的基底神经节的神经元规范。 CCHMC 研究团队的独特专业知识让我们能够采取这种广泛的方法，从而增加我们更深入地了解 Gsx 如何影响因素的机会控制基底神经节发育以及发现导致功能障碍的新基因调控机制某些儿童神经系统疾病。