Elucidating the role of the E3 ubiquitin ligase UBE3B in neuronal activity

项目摘要 自闭症谱系障碍（ASD）是一种神经发育障碍，每54名儿童中就有1名患有自闭症， 显著的表型和遗传异质性。编码E3泛素连接酶的UBE 3B突变， 在智力残疾、言语障碍和ASD患者中发现。具体 UBE 3B的破坏及其底物的随后失调导致 神经发育异常是未知的。我们的研究小组先前已经证明， 基因敲除小鼠模型表现出完全丧失发声和筑巢缺陷，以及减少 树突的复杂性、长度和棘密度。在本论文中，我们将研究UBE 3B的神经功能 通过表征UBE 3B丢失后神经元活性的变化并鉴定其神经元底物。我 将应用互补的电生理和生物化学方法，使用大脑特异性条件反射， Ube 3b敲除小鼠模型（cKOnestin）。我会描述大脑皮层的电生理特性 cKOnestin小鼠的神经元，通过评估其基本特性，包括内在兴奋性和基强度， 电流，以及短期和长期突触可塑性。此外，我将识别神经基质 通过分析蛋白质水平、蛋白质-蛋白质相互作用和泛素化状态来确定UBE 3B的水平。我也会 评估UBE 3B介导的底物修饰，包括泛素化位点和泛素化位点。 链式拓扑成功完成拟议目标将为以下方面的相互作用提供新的见解： 泛素信号传导和神经发育，以及推进我们对特定致病性 神经发育障碍的潜在机制。 UT西南医学中心的特殊研究环境，与集体相结合， 导师团队的专业知识将提供出色的培训。该研究金培训的目标包括 在相关文献中获得知识，并熟练掌握实验程序， 向不同的受众传播科学信息。通过这些目标获得的技能将建立 为独立和成功的科学研究首席研究员奠定了基础。

Project Summary Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects 1 in 54 children and exhibits significant phenotypic and genetic heterogeneity. Mutations in UBE3B, which encodes an E3 ubiquitin ligase, have been identified in patients presenting with intellectual disability, lack of speech, and ASD. The specific mechanism through which disruption of UBE3B, and subsequent dysregulation of its substrates, leads to neurodevelopmental abnormalities is unknown. Our group has previously shown that a Ube3b constitutive knockout mouse model exhibits a complete loss of vocalization and defects in nest building, as well as reduced dendritic complexity, length, and spine density. In this proposal, I will investigate the neuronal function of UBE3B by characterizing changes in neuronal activity following loss of UBE3B and identifying its neuronal substrates. I will apply complimentary electrophysiological and biochemical approaches using a brain-specific conditional Ube3b knockout mouse model (cKOnestin). I will characterize the electrophysiological properties of cortical neurons from cKOnestin mice, by evaluating their basal properties, including intrinsic excitability and rheobase current, and both short-term and long-term synaptic plasticity. Furthermore, I will identify the neuronal substrates of UBE3B through analysis of protein levels, protein-protein interactions, and ubiquitination status. I will also assess the UBE3B-mediated modifications of substrates, including the site of ubiquitination and the ubiquitin chain topology. Successful completion of the proposed aims will provide new insights into the interplay of ubiquitin signaling and neurodevelopment, as well as advance our knowledge of the specific pathogenic mechanisms underlying neurodevelopmental disorders. The exceptional research environment at UT Southwestern Medical Center, combined with the collective expertise of the mentorship team, will provide excellent training. Goals for this fellowship training include becoming knowledgeable in the relevant literature and attaining proficiency in both experimental procedures and communicating scientific information to varied audiences. The skills obtained through these goals will build the foundation for an independent and successful lead investigator in scientific research.