The regulation and function of neuron-specific alternative splicing

鉴于越来越多的证据表明，RNA结合蛋白（RBP）作为遗传原因或诱发风险 神经系统疾病的潜在因素，迫切需要了解其 发育和成熟大脑中的特定细胞功能。与转录因子类似，RBP可能是 某些细胞过程的主要调节器，因为它们的协调目标集。与广泛研究的 由于RBP是转录因子，因此RBP的生理功能在历史上未被充分探索。这十几个人中的大多数 发现表现出组织特异性表达的RBP参与调节神经元选择性剪接。我们 和其他人揭示了在胚胎大脑中选择性剪接的大规模遗传编程， 发育，导致成熟大脑中神经元特异性替代同种型。我们展示了很多 剪接变化由核RBP，多嘧啶片段结合蛋白2（PTBP2）介导。PTBP 2 在神经元分化过程中表现出动态的时间表达， 选择性剪接的编程，以实现延长和连续的神经元 形态转换我们以前的研究表明，PTBP 2在细胞凋亡前的下调， 突触发生是脊柱形成所必需的。我们的最新数据显示，PTBP 2在 在突触形成之前的早期分化神经元。在强有力的初步数据的指导下，我们假设 PTBP2支配神经元特异性剪接以控制神经元极性的起始。这项建议会 解决了神经元极性研究的多个关键障碍，并提供了一个新的功能框架。 选择性剪接的分析。我们在大脑中研究选择性剪接和PTBP2的悠久历史 使我们处于推进这些领域的独特地位。我们的团队在遗传学方面有着互补的专业知识， 神经生物学，分子细胞生物化学和计算生物学，已经证明了成功的 合作。我们已经产生了新的工具和资源，以彻底确定细胞和分子 在皮质神经元中由Ptbp2敲除引起的缺陷。该项目的完成将使我们能够进一步 长期目标是揭示神经元极性的新的遗传、分子和细胞控制， 使神经回路形成的形态发生。

Given the increasing evidence that RNA binding proteins (RBPs) serve as genetic causes or predisposing risk factors underlying a wide spectrum of neurological diseases, a pressing need exists to understand their specific cellular functions in developing and mature brains. Similar to transcription factors, RBPs could be master regulators of certain cellular processes owing to their coordinated target sets. Unlike widely-studied transcription factors, the physiological functions of RBPs are historically underexplored. Most of the dozen RBPs found to exhibit tissue-specific expression are involved in regulating neuronal alternative splicing. We and others have revealed the large-scale genetic programming of alternative splicing during embryonic brain development, resulting in neuron-specific alternative isoforms in mature brains. We show many of these splicing changes are mediated by a nuclear RBP, polypyrimidine tract-binding protein 2 (PTBP2). PTBP2 exhibits dynamic temporal expression during neuronal differentiation and may orchestrate the developmental programming of alternative splicing in order to accomplish the prolonged and continuous neuronal morphological transformations. Our previous study shows that downregulation of PTBP2 prior to synaptogenesis is necessary for spine formation. Our newest data show that PTBP2 has additional functions in early differentiating neurons prior to synapse formation. Guided by strong preliminary data, we hypothesize that PTBP2 governs neuron-specific splicing to control the initiation of neuronal polarity. This proposal will address multiple critical barriers to the study of neuronal polarity and provide a new framework for functional analysis of alternative splicing. Our long history of researching alternative splicing and PTBP2 in the brain places us in a unique position to advance these fields. Our team, with complementary expertise in genetics, neurobiology, and molecular cellular biochemical and computational biology, has demonstrated successful collaborations. We have generated new tools and resource to thoroughly determine the cellular and molecular defects caused by Ptbp2 knockout in cortical neurons. Completion of this project will allow us to further our long-term goal of revealing new genetic, molecular and cellular controls of neuronal polarity and morphogenesis that enables neural circuit formation.