Mechanisms of the programmed cell death of post-embryonic neurons

 描述（由申请人提供）：神经元的程序性细胞死亡（PCD）是通过消除陈旧神经元建立功能性中枢神经系统（CNS）的非常重要的发育事件。在变态发育过程中，脊椎动物和无脊椎动物的某些幼虫神经元选择性地经历PCD。因此，这种发育控制的神经元PCD的破坏导致成人CNS的异常形成。哺乳动物的青春期与两栖动物和昆虫的变态期相当，在此期间也会发生CNS中广泛的神经元修饰。这种过渡性中枢神经系统是青少年情绪和心理不稳定的一个原因。然而，目前还不清楚什么类型的幼年神经元被选择性地注定死亡，以及这种选择是如何进行的。果蝇是解决这些问题的一个很好的模型系统，因为有复杂的神经遗传工具。为了了解果蝇变态过程中神经元PCD的意义和机制，我们提出了两个具体的目标：（1）我们将建立第一个全面的神经解剖学地图的垂死神经元，通过确定其神经化学表型。由于分化的神经元的功能是由它们所携带的神经化学递质决定的，因此这一目标将决定哪些类型（功能）的幼年神经元被编程死亡。除了28个幼虫神经元，我们不知道其他300注定神经元的神经化学身份。为此，我们将开发一种新的体内细胞死亡标记物，以方便地检测垂死的神经元。死亡神经元的鉴定将通过使用特定的gal4驱动程序来完成。(2)我们建议确定在何种程度上严峻，在果蝇中枢神经系统中的一个关键的凋亡基因，在神经元PCD中发挥作用，并了解严峻的表达是如何调节。我们将采用一种新的基因组工程工具CRISPR来产生带有报告基因的grim基因敲入。这些研究将使我们了解如何诱导凋亡基因的表达在变态。在这些工作中，我们希望培养本科生和研究生，并从每个特定的目标发表一篇研究论文。我们在果蝇中的研究将提供一个深入了解神经元PCD在哺乳动物青春期的作用。

 DESCRIPTION (provided by applicant): Programmed cell death (PCD) of neurons is very important developmental event to establish functional central nervous system (CNS) via eliminating obsolete neurons. During metamorphic development, certain larval neurons selectively undergo PCD in both vertebrates and invertebrates. Thus, disruption of such developmentally controlled neuronal PCD results in the aberrant formation of adult CNS. Puberty in mammals is comparable to metamorphosis in amphibians and insects, and extensive neuronal modifications in the CNS take place during this period as well. Such a transitional CNS is a causative reason why teens are emotionally and psychologically unstable. However, it is not well understood what types of juvenile neurons are selectively fated to die, and how such selection is made. Drosophila is an excellent model system to tackle these questions, as sophisticated neuro-genetic tools are available. To understand the significance and mechanisms of neuronal PCD during fly metamorphosis, we propose two specific aims in this proposal: (1) we will establish the first comprehensive neuroanatomical map of dying neurons by identifying their neurochemical phenotypes. Since functions of differentiated neurons are dictated by the neurochemical transmitters they bear, this aim will determine which types (functions) of juvenile neurons are programmed to die. Except for 28 larval neurons, we do not know the neurochemical identities of other ~300 doomed neurons. For this aim, we will develop a new in vivo cell death marker to conveniently detect dying neurons. Identification of dying neurons will be done by using specific gal4 drivers. (2) We propose to determine to what extent grim, a critical apoptotic gene in Drosophila CNS, plays a role in the neuronal PCD and to understand how grim expression is regulated. We will employ a novel genome engineering tool, CRISPR, to generate knock-in of grim with reporter genes. These studies will allow us to understand how apoptotic gene expression is induced during metamorphosis. Throughout these works, we expect to train both undergraduate and graduate students and to publish one research paper from each specific aim. Our proposed studies in Drosophila will provide an insight into the role of neuronal PCD during puberty in mammals.