Regulation of Nodal Signaling in Holoprosencephaly

前脑无裂畸形的节点信号传导调节

• 批准号: 7623961
• 负责人: Jixiang Ding
• 金额: $ 11.66万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7623961
• 关键词: Activins; Alleles; Anterior; Biological Assay; Biological Models; Brain; CFC1 gene; Cell Culture Techniques; Cells; Cleft Lip; Congenital Abnormality; Cultured Cells; Defect; Development; Dorsal; Ectoderm; Embryo; Embryonic Development; Endoderm; Extracellular Protein; Eye; Family; Figs - dietary; Floor; Gene Targeting; Genes; Genetic; Head; Holoprosencephaly; Homeobox Genes; Homeodomain Proteins; Human; IL10 gene; In Vitro; Incisor; Investigation; Lead; Left; Live Birth; Mediating; Mesoderm; Midbrain structure; Molecular; Morphology; Mus; Mutant Strains Mice; Mutation; Nodal; Nuclear Protein; Nuclear Proteins; Pattern; Phenotype; Play; Process; Prosencephalon; Proteins; Regulation; Reporting; Research; Role; Series; Signal Pathway; Signal Transduction; Symptoms; System; Tissues; Transforming Growth Factor beta; Zebrafish; base; craniofacial; density; genetic manipulation; improved; in vivo; insight; interest; malformation; member; notochord; precursor cell; receptor; relating to nervous system; stillbirth

DESCRIPTION (provided by applicant): Holoprosencephaly represents a common birth defect (1:16,000 in live births and 1:250 in stillbirths) with a broad spectrum of craniofacial malformations ranging from distressful cyclopia to mild symptom of a single central incisor. It is caused by defects in the specification of the ventral forebrain (a part of the anterior axial midline), which subsequently lead to incomplete separation of the brain into the left and right hemispheres. Recent studies indicated that Nodal signaling plays a central role in controlling midline development, we therefore will focus on the regulation of Nodal signaling in mouse embryogenesis with a special interest in anterior axial midline formation. Nodal is a member of the transforming growth factor beta (TGF-beta) superfamily that utilizes a signaling pathway defined by Activin type I and II receptors, Smad2 and 4, and FoxH1(FAST). Importantly, members of the EGF-CFC family of extracellular proteins such as mouse Cripto are essential co-factors for Nodal. We previously reported a Cripto null allele, and recently we generated a Cripto hypomorphic allele, Cripto3-loxP, by genetic manipulation. Approximately 50% of the Cripto3-loxP/CriptoNull mice displayed a wide range of axial midline defects resembling holoprosencephaly. In contrast, TGIF is a homeobox gene encoding a nuclear protein that antagonizes TGF-beta signaling by blocking Smad2 function. Interestingly, mutations in human TGIF gene are associated with holoprosencephaly, suggesting its function in axial midline formation, presumably through regulating Nodal/Smad2 signaling pathway. Based on these results, we will pursue the following specific aims in the proposed research: I) Analysis of the Cripto3-loxP/CriptoNull mice as a model system for ventral forebrain defects and HPE by detailed analysis of the defects in Cripto3-loxP/CriptoNull mice at morphology and molecular levels; II) Investigation of mechanisms underlying Cripto function in mouse axial midline formation by identifying the tissues and cells where Cripto is functioning and downstream target genes of Cripto; III) Investigation of TGIF function in mouse axial midline development by generating TGIF null embryos and examining the modulation of Nodal signaling by TGIF. These studies should improve our understanding of mammalian axial midline formation and human holoprosencephaly.

描述（由申请人提供）：前脑无裂畸形是一种常见的出生缺陷（活产1：16，000，死产1：250），具有广泛的颅面畸形，从令人痛苦的独眼畸形到单个中切牙的轻度症状。它是由腹侧前脑（前轴中线的一部分）的规格缺陷引起的，这随后导致大脑不完全分离成左右半球。最近的研究表明，Nodal信号在控制中线发育中起着核心作用，因此，我们将重点关注Nodal信号在小鼠胚胎发育中的调节，特别是在前轴中线形成中。Nodal是转化生长因子β（TGF-β）超家族的成员，其利用由激活素I型和II型受体、Smad 2和4以及FoxH 1（FAST）定义的信号传导途径。重要的是，细胞外蛋白的EGF-CFC家族的成员，如小鼠Cripto是Nodal的重要辅助因子。我们以前报道了一个Cripto无效等位基因，最近我们通过遗传操作产生了一个Cripto亚纯型等位基因Cripto 3-loxP。大约50%的Cripto 3-loxP/Criptoplasty小鼠显示出广泛的轴向中线缺陷，类似于前脑无裂畸形。相比之下，TGIF是一个同源框基因，编码一种核蛋白，通过阻断Smad 2功能来拮抗TGF-β信号传导。有趣的是，人类TGIF基因的突变与前脑无裂畸形相关，提示其在轴向中线形成中的功能，可能通过调节Nodal/Smad 2信号通路。基于这些结果，我们将在拟议的研究中实现以下具体目标：I）通过在形态学和分子水平上详细分析Cripto 3-loxP/Cripto 3小鼠中的缺陷，分析Cripto 3-loxP/Cripto 3小鼠作为腹侧前脑缺陷和HPE的模型系统;第二章）通过鉴定Cripto发挥作用的组织和细胞，研究Cripto在小鼠中轴中线形成中的作用机制，III）通过产生TGIF无效胚胎并检查TGIF对Nodal信号传导的调节来研究TGIF在小鼠轴向中线发育中的功能。这些研究将提高我们对哺乳动物中轴线形成和人类前脑无裂畸形的认识。