Control of Asymmetric Neural Stem Cell Division

描述(申请人提供)：大脑的正常运作依赖于不同类型的神经元和神经胶质细胞的协调，这些神经元和胶质细胞出现在不同的位置，并建立复杂的联系。了解这些脑细胞是如何正常发育的，是神经疾病治疗干预的关键，特别是那些具有发育病因的疾病。神经干细胞(NSCs)在胚胎发育和成年生活中都在神经元和GILA的生成中发挥着关键作用。尽管它们在临床上很重要，但人们对哺乳动物神经干细胞的身份和位置以及它们的行为在体内是如何调控的知之甚少。果蝇神经干细胞为此类研究提供了极好的机会。这项建议的长期目标是通过对果蝇的细胞生物学、遗传学和分子分析，了解调控神经干细胞分化和自我更新的分子和细胞机制。果蝇中枢神经系统干细胞(神经母细胞)经历自我更新的不对称细胞分裂。每次分裂后，一个子细胞仍然是干细胞，另一个则致力于分化。已经确定了其不对称分离本质上改变细胞命运选择的决定因素。Numb决定簇不对称分离需要Numb蛋白的伴侣(PON)。在这项提案中，我们计划以PON为起点，从机械上理解细胞命运决定因素的不对称分离是如何实现的。我们将首先对PON定位结构域进行详细的表征，以确定该结构域中导致其不对称定位的分子特征以及通过该结构域发挥功能的蛋白质。为了确定控制PON本地化的其他因素，我们将测试肌球蛋白马达分子的参与。我们还将进行正向突变筛选，以PON-绿色荧光蛋白(GFP)报告为检测系统，系统地鉴定控制NSCs不对称分裂的关键基因。鉴于控制许多发育过程的分子机制的保守性，调控NSCs行为的基因和遗传程序很可能也将在果蝇和哺乳动物之间保守。我们相信，从我们的研究中获得的知识将影响哺乳动物神经干细胞的研究，并有助于理解和治疗人类的神经疾病。

DESCRIPTION (provided by applicant): Proper functioning of the brain depends on the coordination of diverse types of neurons and glia, which arise at distinct locations and make intricate connections. Understanding how these brain cells are normally developed holds the key to therapeutic intervention of neurological diseases, especially those with developmental etiology. Neural stem cells (NSCs) play critical roles in generating neurons and gila during both embryonic development and adult life. Despite their clinical importance, little is known about the identity and location of the mammalian NSCs and how their behavior is regulated in vivo. The Drosophila NSCs provide an excellent opportunity for such studies. The long-term goal of this proposal is to understand the molecular and cellular mechanisms regulating the differentiation and self-renewal of NSCs, using cell biological, genetic, and molecular analyses in Drosophila. The Drosophila central nervous system stem cells (neuroblasts) undergo self-renewing asymmetric cell divisions. After each division, one daughter cell remains as a stem cell and the other is committed to differentiation. Determinants whose asymmetric segregation serves to intrinsically alter cell fate choices have been identified. The asymmetric segregation of determinant Numb requires Partner of Numb (Pon) protein. In this proposal, we plan to use Pon as a starting point to achieve a mechanistic understanding of how the asymmetric segregation of cell fate determinants is accomplished. We will first carry out a detailed characterization of the Pon localization domain to identify the molecular features in this domain that contribute to its asymmetric localization and proteins that act through this domain to exert their function. To identify other players that control the localization of Pon, we will test the involvement of myosin motor molecules. We will also perform a forward mutagenesis screen, using a Pon-green fluorescent protein (GFP) reporter as the assay system, to systematically identify key genes that control the asymmetric division of NSCs. Given the conservation of molecular mechanisms that control many developmental processes, it is highly likely that the genes and genetic programs regulating the behavior of NSCs will also be conserved between Drosophila and mammals. We believe that knowledge gained from our study will influence mammalian NSC research and contribute to the understanding and treatment of neurological diseases in humans.