Project III - Modeling meningomyelocele alleles and response to folic acid diet in mouse

项目 III - 模拟小鼠脑膜脊髓膨出等位基因和对叶酸饮食的反应

基本信息

批准号：
10300072
负责人：
Lee A. Niswander
金额：
$ 26.75万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-12-01 至 2025-11-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10300072
关键词：
22q11.2 Actins Alleles Biological Cell Proliferation Cells Cephalic Chromatin Cilia Collection Complement Congenital Abnormality DNA Methylation Data Development Diet Diet Modification Ectoderm Embryo Environmental Impact Environmental Risk Factor Epigenetic Process Ethylnitrosourea Failure Folic Acid Gene Expression Gene Mutation Genes Genetic Genetic Transcription Genome Goals Gold Grain Head Human Individual Knock-in Mouse Knockout Mice Link Mammals Mediating Meningomyelocele Mesoderm Modeling Molecular Morbidity - disease rate Morphology Mus Mutagenesis Mutant Strains Mice Mutate Mutation Neural Tube Closure Neural Tube Defects Neural tube Nucleotide Biosynthesis Pathway interactions Patients Pattern Penetrance Phenocopy Phenotype Point Mutation Process Program Research Project Grants Proteins Regulation Risk Risk Factors Role S-Adenosylmethionine SHH gene Signal Transduction Standard Model Testing Time Tissue Model Transforming Growth Factor beta Tube Variant WNT Signaling Pathway Work cell type cilium biogenesis de novo mutation epigenome folic acid metabolism folic acid supplementation fortification gene environment interaction gene function gene interaction genetic testing human model imaging platform insight live cell imaging methylome mortality mouse model mutant nerve stem cell neural plate novel offspring planar cell polarity programs response smoothened signaling pathway transcriptome

项目摘要

Abstract – Project III Modeling meningomyelocele alleles and response to folic acid diet in mouse The overall hypothesis of the Program Project grant is that de novo mutations contribute to meningomyelocele (MM) risk and that folic acid (FA) influences the genome through chromatin accessibility and modulation of gene expression, to alter this risk. The mouse is considered the gold standard model for human neural tube defects (NTDs), because development is highly conserved in mammals, leading to similar types of cranial and caudal NTDs, utilizing similar genes, and responding to similar environmental factors. The mouse has been invaluable in defining genes required for neural tube closure, now numbering over 250 genes, and highlighting the need for exquisite precision of cell proliferation, actin regulation, planar cell polarity/WNT signaling, cilia/Hedgehog signaling, and FA metabolism. Many mouse NTD models show allele-specific effects, where for example, homozygous null mice are embryonic lethal, heterozygous null mice are healthy, but specific point mutations, some heterozygous, some homozygous, show NTD. In many of these mouse models, NTDs often occur in less than 100% of offspring, even in an entirely pure genetic background, reflecting background-independent partial penetrance. Like in human, the penetrance and expressivity of NTD phenotypes can be influenced by FA exposure, with about half of genes tested to date showing FA responsiveness. FA has been supplemented in grains in the US diet since 1998, regulating biosynthesis of nucleotides and S-adenosylmethionine, the universal methyl donor for DNA methylation. To account for these observations, we hypothesize that NTD risk is established by mutations in a core set of genes, with risk modified by FA-dependent changes in the epigenome. Project III has already assembled the following preliminary data: 1] Performed recessive ENU- mutagenesis screens for genes essential for neural tube closure. 2] Assembled a growing collection of genes and alleles from more than 30 NTD mutants. 3] Demonstrated mutations in primary ciliary genes underlying several mouse NTD mutants. 4] Demonstrated an impact of FA on penetrance and expressivity of murine NTDs. 5] Developed live-cell imaging platform to observe mammalian neural tube closure in real-time. 6] Modeled meningomyelocele in mouse for the human MM gene WLS. This proposal focuses on evaluating genes and alleles emerging from Project I and II as risk factors for MM, as well as the FA-dependent changes in the methylome and transcriptome that can influence this risk. Altogether, the goal of Project III is to define the relationships and interplay between mammalian MM mutations and FA influences on penetrance and expressivity. Aim 1. Model human meningomyelocele (MM) variants and genetic interactions to assess expressivity. Aim 2. Assess impact of folic acid on NTD expressivity on a gene-by-gene basis. Aim 3. Assess impact of folic acid on the neural tube at the level of single cell transcriptome, methylome and chromatin accessibility landscape.

摘要 – 项目 III 模拟小鼠脑膜脊髓膨出等位基因和对叶酸饮食的反应该计划项目拨款的总体假设是新生突变导致脑膜脊髓膨出 (MM) 风险以及叶酸 (FA) 通过染色质可及性和基因调节影响基因组表达，以改变这种风险，小鼠被认为是人类神经管缺陷的黄金标准模型。（NTD），因为哺乳动物的发育高度保守，导致颅骨和尾骨的类型相似 NTDs利用相似的基因并对相似的环境因素做出反应，老鼠的价值是无价的。定义神经管闭合所需的基因，目前已对 250 多个基因进行了编号，并强调了细胞增殖、肌动蛋白调节、平面细胞极性/WNT信号、纤毛/Hedgehog的精确度许多小鼠 NTD 模型表现出等位基因特异性效应，例如，纯合子小鼠是胚胎致死的，杂合子小鼠是健康的，但有特定的点突变，一些杂合子、一些纯合子表现出 NTD 在许多此类小鼠模型中，NTD 的发生率通常较低。超过 100% 的后代，即使在完全纯的遗传背景下，也反映了背景无关的部分与人类一样，NTD 表型的外显率和表达性会受到 FA 的影响。迄今为止，大约一半的基因测试表明 FA 已被补充。自 1998 年起，谷物就出现在美国饮食中，调节核苷酸和 S-腺苷甲硫氨酸的生物合成。 DNA 甲基化的甲基供体为了解释这些观察结果，我们追踪 NTD 风险。由一组核心基因的突变建立，风险通过 FA 依赖性变化而改变表观基因组项目 III 已经收集了以下初步数据： 1] 进行了隐性 ENU- 诱变筛选神经管闭合所必需的基因 2] 收集了越来越多的基因。以及来自超过 30 个 NTD 突变体的等位基因 3] 已证实初级纤毛基因发生突变。几种小鼠 NTD 突变体。4] 证明了 FA 对小鼠 NTD 外显率和表达能力的影响。 5] 开发活细胞成像平台来实时观察哺乳动物神经管闭合情况 6] 建模。针对人类 MM 基因 WLS 的小鼠脑膜脊髓膨出该提案重点评估基因和项目 I 和 II 中出现的等位基因作为 MM 的风险因素，以及 FA 依赖性变化总而言之，项目 III 的目标是定义可能影响这种风险的甲基化组和转录组。哺乳动物 MM 突变和 FA 之间的关系和相互作用对外显率和表现力。目标 1. 建立人类脑膜脊髓膨出 (MM) 变异和遗传相互作用模型以评估表达性。目标 2. 逐个基因评估叶酸对 NTD 表达性的影响。目标 3. 在单细胞转录组、甲基化组水平评估叶酸对神经管的影响和染色质可及性景观。