How neuronal polarity is established in vivo

描述(申请人提供)：项目摘要：正常的人类认知依赖于在发育过程中组装的功能神经元电路。神经元的极性和形态对于形成适当的神经元连接是不可或缺的，尽管神经元的极性和形态是如何在体内建立的这个问题在很大程度上仍然没有答案。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)鉴定筛选中发现的一个极性突变体；(3)鉴定果蝇神经元极性/形态基因在哺乳动物中的同源基因，并分析它们在培养的哺乳动物神经元中的功能。遗传筛查使用GFP构建物来可视化活的苍蝇胚胎和幼虫中的一类多极神经元，从而简化了筛查过程。筛查发现了一种极性突变，其特征是首先识别与突变相对应的基因，然后确定其发挥作用的机制。最后，为了更好地了解调节神经元极性和形态的保守机制，我们将分析培养的哺乳动物神经元中在遗传屏幕上识别的基因。具体地说，将鉴定苍蝇突变体的哺乳动物同源物，并将使用培养的海马神经元来评估它们在神经元极性/形态中的作用。总之，这项建议的目标是识别神经元极性和形态的新调节器，并表征它们在果蝇和培养的哺乳动物神经元中的功能。因此，这些研究的结果可能有助于阐明调节神经元极性和形态的保守机制。公共卫生相关性：包括弱脑和智力低下在内的多种人类发育障碍与神经元极性和/或形态异常有关。这个建议的目标是了解神经元的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电路是如何组装的。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.