Alternative splicing and nonsense-mediated mRNA decay in neural development

描述(由申请人提供)：无意义介导的信使核糖核酸衰变(NMD)途径的缺陷最近被认为与多种神经精神疾病有关。然而，这一途径在大脑中还没有得到很好的研究，神经元中NMD的破坏也没有被表征。我们最近发现了NMD通路在神经系统中的一个新的调节作用。NMD通过与选择性剪接调控相结合，控制突触后密度蛋白95(PSD-95)的表达水平，突触后密度蛋白95是兴奋性PSD的重要支架蛋白。这种调控机制类似于转录调控的输出，但目前尚不清楚NMD还调控哪些其他天然神经元转录本。我的长期目标是了解NMD介导的调节在神经系统中的作用，以及NMD的错误如何导致神经精神障碍。这项建议的目的是表征NMD途径缺陷所导致的基本发育缺陷，并系统地鉴定啮齿动物神经元中的生理性NMD底物。我已经建立了一个NMD缺陷的小鼠模型，并为这个提议开发了各种技术。在强大的初步数据的指导下，我将追求两个具体目标：1)在全基因组范围内鉴定对神经元发育至关重要的NMD靶点；2)表征发育过程中对NMD途径的生理需求。在初步数据的基础上，将在体内和体外对NMD缺陷神经元的突触发育的两个重要方面--脊椎形态和谷氨酸受体的突触表达进行深入的研究。鉴定神经元中的天然NMD底物将有助于了解NMD作为基因表达的主动调控途径而不是被动的质量控制机制的频率。了解NMD在大脑中的遗传作用和特定靶点为理解各种神经精神疾病的发病机制提供了一个新的视角，并可能有助于指出治疗干预的共同靶点/途径。我有细胞神经科学和RNA分子生物学的背景。我处于一个独特的位置，可以为拟议的研究领域做出贡献。为了进一步为我的长期研究目标做准备，我计划寻求培训，以补充我现有的技术技能，并进一步发展我的专业技能。加州大学洛杉矶分校有一个高度协作的环境，非常适合这个项目和我实现这些目标。我的导师道格拉斯·布莱克博士是另类剪接调控方面的世界级专家之一。我还有一个由凯尔西·马丁博士、汤姆·奥戴尔博士和威廉·杨博士组成的咨询委员会，为神经科学提供补充意见。我的导师团队有一个详细的计划，以促进我的研究进展和科学的职业发展。总而言之，我的教育和研究经验，加上强大和支持的指导团队，使我成为这个研究项目和K99/R00奖的理想人选。

DESCRIPTION (provided by applicant): Defects in the nonsense-mediated mRNA decay (NMD) pathway have recently been implicated in multiple neuropsychiatric diseases. However, this pathway has not been well studied in the brain and disruption of NMD in neurons has not been characterized. We recently discovered a novel regulatory role of the NMD pathway in the nervous system. Through coupling to alternative splicing regulation, NMD controls the expression level of postsynaptic density protein 95 (PSD-95), an essential scaffold protein of the excitatory PSD. This mechanism of regulation is similar to the output of transcriptional control, but it is unclear what other natural neuronal transcripts are regulated by NMD. My long term goal is to understand the role of NMD- mediated regulation in the nervous system, and how errors in NMD can lead to neuropsychiatric disorders. The objective of this proposal is to characterize fundamental developmental defects resulting from deficiencies in the NMD pathway and systematically identify physiological NMD substrates in rodent neurons. I have already generated an NMD deficient mouse model and developed various techniques for this proposal. Guided by strong preliminary data, I will pursue two specific aims: 1) Genome-wide identification of NMD targets important for neuronal development; 2) Characterize the physiological requirement for the NMD pathway during development. Based on preliminary data, two important aspects of synapse development, spine morphology and synaptic expression of glutamate receptors, will be examined thoroughly in NMD deficient neurons both in vivo and in vitro. Identification of natural NMD substrates in neurons will shed light on how frequently NMD is used as an active regulatory pathway of gene expression rather than a passive quality-control mechanism. Knowledge about the genetic roles and specific targets of NMD in brain provides a novel perspective for understanding the pathogenesis of various neuropsychiatric diseases and may help point to the common targets/pathways for therapeutic intervention. I have a background in both cellular neuroscience and RNA molecular biology. I am in a unique position to contribute to the proposed research area. To further prepare myself for my long-term research goal, I plan to seek training that will complement my existing technical skills and furthe develop my professional skills. UCLA has a highly collaborative environment ideal to this project and for me to achieve these goals. My mentor, Dr. Douglas Black, is one of the world-class experts in alternative splicing regulation. I also have an advisory committee that consists of Dr. Kelsey Martin, Dr. Tom O'Dell, and Dr. William Yang and provide complementary inputs on neuroscience. My mentor team has a detailed plan to facilitate my research progress and scientific career development. In summary, my educational and research experience together with a strong and supportive mentoring team make me an ideal candidate for this research project and the K99/R00 award.