How neuronal polarity is established in vivo

描述（由申请人提供）：项目概述：正常的人类认知依赖于在发育过程中组装的功能性神经元回路。神经元的极性和形态是形成适当的神经元连接不可或缺的，虽然如何在体内建立神经元的极性和形态的问题仍然在很大程度上没有答案。以果蝇为模型系统，本研究的目的是（1）进行体内正向遗传筛选，以发现新的神经元极性和形态调节因子，（2）表征在此筛选中鉴定的极性突变体，（3）鉴定果蝇神经元极性/形态基因的哺乳动物同源物，并分析其在培养的哺乳动物神经元中的功能。遗传筛选使用GFP构建体来可视化活体苍蝇胚胎和幼虫中的一类多极神经元，从而促进筛选过程。筛选发现了一个极性突变体，其特征在于首先识别与突变对应的基因，然后确定其功能机制。最后，为了更好地理解调节神经元极性和形态的保守机制，将在培养的哺乳动物神经元中分析在遗传筛选中鉴定的基因。具体而言，将鉴定果蝇突变体的哺乳动物同源物，并使用培养的海马神经元评估其在神经元极性/形态学中的作用。总之，本建议的目标是确定新的调节神经元极性和形态，并在苍蝇和培养的哺乳动物神经元的功能进行表征。因此，这些研究的结果将可能揭示保守的机制调节神经元极性和形态。公共卫生相关性：多种人类发育障碍，包括无脑畸形和智力迟钝，与异常的神经元极性和/或形态学有关。这个提议的目标是了解神经元极性和形态是如何在体内建立的，这将有助于我们理解神经回路是如何组装的。这些知识可以应用于治疗人类疾病。

DESCRIPTION (provided by applicant): Project Summary: Normal human cognition relies on functional neuronal circuits that are assembled during development. Neuronal polarity and morphology are integral to forming proper neuronal connections, although the question of how neuronal polarity and morphology are established in vivo remains largely unanswered. Using the fruit fly as a model system, the aims of this proposal are to (1) conduct an in vivo forward genetic screen to uncover novel neuronal polarity and morphology regulators, (2) characterize a polarity mutant identified in this screen and (3) identify the mammalian homologs of fly neuronal polarity/morphology genes and analyze their function in cultured mammalian neurons. The genetic screen uses a GFP construct to visualize a class of multipolar neurons in living fly embryos and larvae, facilitating the screening process. The screen has uncovered a polarity mutant, which will be characterized by first identifying the gene corresponding to the mutation and then determining the mechanism by which it functions. Lastly, to better understand the conserved mechanisms regulating neuronal polarity and morphology, genes identified in the genetic screen will be analyzed in cultured mammalian neurons. Specifically, mammalian homologs of the fly mutants will be identified and their role in neuronal polarity/morphology will be assessed using cultured hippocampal neurons. In conclusion, the goal of this proposal is identify novel regulators of neuronal polarity and morphology and to characterize their function in both flies and cultured mammalian neurons. Therefore, the results of these studies will likely shed light on conserved mechanisms regulating neuronal polarity and morphology. Public Health Relevance: Multiple human developmental disorders, including lissencephaly and mental retardation, are associated with abnormal neuronal polarity and/or morphology. This goal of this proposal is understand how neuronal polarity and morphology are established in vivo, which will contribute to our understanding of how neural circuits assemble. Such knowledge can be applied to treating human disorders.