Pitx2: Molecular Mechanisms in Eye Development and Disease

Pitx2：眼睛发育和疾病的分子机制

基本信息

批准号：
7633163
负责人：
PHILIP J GAGE
金额：
$ 36.77万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-09-01 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7633163
关键词：
Ablation Accounting Alleles Anterior Axenfeld-Rieger syndrome Candidate Disease Gene Cell Death Cell Proliferation Cell physiology Cells Data Defect Development Diagnostic Disease Dose Ectoderm Embryo Engineering Event Eye Eye Development Eye diseases Eyelid structure Future Gene Targeting Genes Genetic Genetic screening method Glaucoma Goals Grant Homeobox Genes Human Knockout Mice Knowledge Laboratories Link Mediating Mesenchyme Mesoderm Methods Modeling Modification Molecular Mus Mutant Strains Mice Mutation Neural Crest Pathway interactions Patients Pattern Phenotype Process Publishing Research Personnel Role Series Signal Pathway Signal Transduction Signaling Pathway Gene Stem cells Stream Structure Surface Technology Testing Tissue-Specific Gene Expression Tissues Work base cell type gene function genetic analysis homeodomain knockout gene mutant orbit muscle programs relating to nervous system transcription factor treatment strategy

项目摘要

DESCRIPTION: Genetic networks regulating normal development of anterior segment structures are poorly understood. Mice are ideal models for determining the basic mechanisms contributing to normal eye development and for analyzing genetic eye disease. Mutations in the homeobox gene PITX2 result in Axenfeld-Rieger Syndrome (ARS), an autosomal dominant disease causing congenital anterior segment defects and glaucoma. I cloned Pitx2 from mouse and used gene targeting in mice to generate a series of Pitx2 alleles that allow for global or conditional ablation of gene function, and the ability to vary gene dose. Based on published data and our own preliminary results, we hypothesize a central role for Pitx2 in periocular mesenchyme during eye development for differentiation of ocular cell types derived from mesenchyme and for mesenchyme expression of extrinsic factors required for normal development of surface and neural ectoderm in the eye. In the previous grant cycle, we demonstrated early Pitx2 expression in ocular neural crest and mesoderm, established that Pitx2 function in neural crest is required for multiple steps in eye development, and identified a role for PITX2 in regulating Wnt signaling in neural crest that could account for Pitx2 mutant phenotypes. The overall goals of this proposal are to use our series of murine Pitx2 alleles to determine the role(s) of Pitx2 in mesoderm during eye development and to establish the mechanistic and functional relationships between Pitx2 and components of the Wnt signaling pathway. In Aim 1, we will test the hypothesis that Pitx2 has distinct functions in ocular mesoderm using a conditional targeting strategy. In Aim 2, we will test a specific Wnt signaling pathway gene as a direct PITX2 target and identify its morphological and molecular roles in eye development to see if this gene accounts for components of the Pitx2 phenotype. We will also screen human patients with specific anterior segment defects and glaucoma for mutations in this gene. In Aim 3, we will directly test for genetic interactions between Pitx2 and the Wnt pathway gene in mice as a mechanism for modification of the Pitx2 mutant phenotype since phenotypic variability is a key feature of ARS. This multifaceted approach will provide specific mechanistic details about the functions of Pitx2 in eye development and new knowledge into more general fundamental mechanisms of periocular mesenchyme in this process. This basic information is essential for understanding eye disease, including glaucoma.

描述：调节前部结构正常发育的遗传网络知之甚少。小鼠是确定有助于正常眼发育和分析遗传眼病的基本机制的理想模型。同源基因PITX2的突变导致Axenfeld-Rieger综合征（ARS），ARS是一种常染色体显性疾病，导致先天性前部缺陷和青光眼。我从小鼠中克隆了pitx2，并在小鼠中使用了基因靶向，以生成一系列的PITX2等位基因，这些等位基因允许基因功能的全局或条件消融，以及改变基因剂量的能力。基于已发布的数据和我们自己的初步结果，我们假设眼睛发育过程中PITX2在眼周间质中的核心作用是分化源自间充质的眼细胞类型，以及眼睛中表面和神经表面表面正常发育所需的外源性因子的外源性表达。在上一个赠款周期中，我们证明了眼前神经rest和中胚层中的早期PITX2表达，确定了眼睛发育中多个步骤中需要PITX2功能，并且确定了PITX2在调节神经crest中Wnt信号传导中的作用，这可以考虑PITX2突变体表型。该提案的总体目标是使用我们的一系列鼠PITX2等位基因来确定pitx2在眼胚层发育过程中的作用，并建立pitx2与Wnt信号通路的组件之间的机械和功能关系。在AIM 1中，我们将检验以下假设：PITX2使用条件靶向策略在眼皮中具有不同的功能。在AIM 2中，我们将测试特定的Wnt信号通路基因作为直接的PITX2靶标，并确定其在眼睛发育中的形态和分子作用，以查看该基因是否占PITX2表型的成分。我们还将筛选患有特定前部缺陷和青光眼的人类患者，以进行该基因中的突变。在AIM 3中，我们将直接测试小鼠PITX2与Wnt途径基因之间的遗传相互作用，这是修饰Pitx2突变体表型的机制，因为表型变异性是ARS的关键特征。这种多方面的方法将在此过程中提供有关PITX2在眼睛发育中功能以及新知识的功能的特定机械细节，并在此过程中提供更通用的基本机制。此基本信息对于理解包括青光眼在内的眼科疾病至关重要。