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UBE3A gain-of-function and parent-of-origin influence on neurodevelopmental phenotypes

UBE3A 功能获得和亲本对神经发育表型的影响

基本信息

批准号：
10441267
负责人：
BENJAMIN D PHILPOT
金额：
$ 64.84万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10441267
关键词：
Adult Affect Age Alleles Behavioral Symptoms Birth Brain Cell Cycle Cell Differentiation process Cell Proliferation Cells Cerebral cortex Cyclic AMP-Dependent Protein Kinases Data Development Disease Embryo Engineering Equilibrium Event Exhibits Functional disorder Gene Duplication Genes Genotype Human Impairment Individual Inherited Knowledge Lead Life Ligase Link Macrocephaly Modeling Molecular Mus Mutant Strains Mice Mutation Neurodevelopmental Disorder Neurons Parents Pathway interactions Perinatal Phenotype Phosphorylation Phosphorylation Site Proteomics Research Risk Role Signal Pathway Signal Transduction Structure Symptoms Testing Thick Threonine UBE3A gene Weight Work autism spectrum disorder base behavioral phenotyping brain behavior brain dysfunction brain overgrowth cell type de novo mutation effective therapy experimental study gain of function gain of function mutation in vivo Model individuals with autism spectrum disorder insight lymphoblast mouse model multicatalytic endopeptidase complex mutant nerve stem cell neurodevelopment novel novel therapeutic intervention postnatal prenatal proband progenitor single-cell RNA sequencing stem cell proliferation ubiquitin ligase ubiquitin-protein ligase unpublished works

项目摘要

PROJECT SUMMARY UBE3A is an E3 ubiquitin ligase that targets itself and other substrates for proteasomal degradation. In the developing brain, neuronal progenitors and immature neurons biallelically express Ube3a, but as neurons mature, Ube3a expression becomes restricted to the maternally-inherited allele. Mutations that elevate maternal or paternal Ube3a are linked to autism risk, but precisely how UBE3A excess impairs neurodevelopment is unclear. Recently, we found that phosphorylation of threonine 485 (T485) inhibits UBE3A ubiquitin ligase activity. UBE3A T485 phosphorylation initiates embryonically and peaks at birth, suggesting that phosphorylation might protectively limit UBE3A activity during early cortical development. Additionally, we found that an autism-linked de novo mutation in UBE3A (T485A) disrupts this phosphorylation site, effectively locking UBE3A always-on. We engineered a mouse that precisely models this human UBE3A T485A mutation, allowing us to evaluate how this novel gain-of-function mutation affects brain and behavioral phenotypes when inherited maternally or paternally. In preliminary studies, we found that cortical thickness and brain weight were significantly increased at birth in all three Ube3a T485A genotypes (paternal, maternal, homozygous). Mutations in other autism-linked genes increase brain weight to a similar extent. These findings suggest a novel and previously unrecognized prenatal function for UBE3A in brain development. All three Ube3a T485A mutant genotypes also had behavioral phenotypes consistent with neurodevelopmental disorders. Since little is known about how UBE3A impairs brain function at any age, we performed unbiased proteomics to identify brain-relevant substrates. Our preliminary proteomics data link UBE3A directly to the proteasome, a structure that can influence the cell cycle and signaling pathways important for brain development. These and other data lead us to hypothesize that UBE3A T485A alters the balance of cell proliferation and differentiation during brain development, in part by impairing proteasome function, and contributes to autism-associated phenotypes later in life. The experiments in this proposal will rigorously demonstrate that (1) UBE3A T485A alters the balance of progenitor proliferation and differentiation in the cerebral cortex, (2) parent-of-origin inheritance of Ube3a T485A influences autism-related brain and behavioral phenotypes, and (3) UBE3A T485A interacts with the proteasome and impairs proteasome function in the brain. Unbiased proteomics experiments will identify brain-relevant substrates of UBE3A, and broaden our understanding of which molecular pathways are affected by gain-of-function mutations that enhance UBE3A activity.

项目摘要 UBE 3A是一种E3泛素连接酶，靶向自身和其他底物进行蛋白酶体降解。在发育中的脑、神经元祖细胞和未成熟神经元双等位地表达Ube 3a，但作为神经元成熟时，Ube 3a的表达仅限于母系遗传的等位基因。突变会提高母亲或父亲的Ube 3a与自闭症风险有关，但确切地说，UBE 3A过量如何损害神经发育尚不清楚。最近，我们发现苏氨酸485（T485）的磷酸化抑制了 UBE 3A泛素连接酶活性。UBE 3A T485磷酸化在胚胎中开始并在出生时达到峰值，提示磷酸化可能在早期皮质发育期间保护性地限制UBE 3A活性。此外，我们发现UBE 3A（T485 A）中与自闭症相关的从头突变破坏了这种磷酸化，我们设计了一只小鼠，它精确地模拟了人类UBE 3A， T485 A突变，使我们能够评估这种新的功能获得性突变如何影响大脑和行为表型是由母系或父系遗传的。在初步研究中，我们发现皮质厚度和脑重在出生时在所有三种Ube 3a T485 A基因型（父亲，母亲，纯合子）。其他自闭症相关基因的突变也会在类似程度上增加大脑重量。这些研究结果表明，UBE 3A在大脑发育中具有一种新的和以前未被认识的产前功能。所有三个Ube 3a T485 A突变基因型也具有与神经发育相关的行为表型，紊乱由于对UBE 3A如何在任何年龄损害大脑功能知之甚少，我们进行了无偏蛋白质组学来识别大脑相关底物。我们初步的蛋白质组学数据将UBE 3A直接与蛋白酶体，一种可以影响细胞周期和大脑重要信号通路的结构发展这些和其他数据使我们假设UBE 3A T485 A改变了细胞的平衡，在大脑发育过程中的增殖和分化，部分是通过损害蛋白酶体功能，并在以后的生活中导致自闭症相关的表型。该提案中的实验将严格证明（1）UBE 3A T485 A改变祖细胞增殖和分化的平衡在大脑皮层中，（2）Ube 3a T485 A的双亲遗传影响自闭症相关的大脑，行为表型;（3）UBE 3A T485 A与蛋白酶体相互作用并损害蛋白酶体功能在大脑中。无偏见的蛋白质组学实验将确定UBE 3A的脑相关底物，并扩大我们对哪些分子通路受到功能获得性突变的影响的理解， UBE 3A活性。