Elucidating the Numb Signaling Pathway

阐明麻木信号通路

• 批准号: 8659520
• 负责人: WEIMIN ZHONG
• 金额: $ 35.12万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-15 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8659520
• 关键词: Address; Adopted; Aging; Behavior; Biological Models; Cell Cycle; Cell Cycle Progression; Cell division; Cells; Daughter; Defect; Development; Disease; Drosophila genus; Enhancers; Equilibrium; Genes; Genetic Screening; Goals; Golgi Apparatus; Homeostasis; Homologous Gene; Individual; Injury; Invertebrates; Knowledge; Maintenance; Mammals; Mediating; Molecular; Mus; N-terminal; Neuraxis; Neurons; Organogenesis; Population; Process; Production; Protein Binding; Proteins; Signal Pathway; Signal Transduction; Signaling Molecule; Signaling Protein; Source; Specific qualifier value; Stem Cell Research; Stem cells; Therapeutic Uses; Time; Tissues; To specify; Variant; cancer stem cell; cell fate specification; daughter cell; dosage; gain of function; insight; interest; meetings; mouse Numb protein; mutant; nerve stem cell; neurogenesis; novel; numb protein; precursor cell; progenitor; public health relevance; reconstitution; relating to nervous system; response; self-renewal; stem; tissue repair

DESCRIPTION (provided by applicant): Asymmetric cell division, a process by which a cell divides to produce two different daughter cells, is essential for generating cellular diversity during development. Such divisions are also an attractive means for stem cells to balance the competing needs of self-renewal and differentiation during organogenesis and tissue maintenance, by producing one daughter that remains as a stem cell and the other that differentiates. In Drosophila, Numb, a cytoplasmic signaling protein, localizes asymmetrically in dividing precursor cells and segregates primarily into one daughter cell. This asymmetric Numb inheritance is essential for the two daughter cells to adopt different fates. We have been using the mammalian numb proteins, Numb and Numbl, as an entry point, and neurogenesis in mice as a model system, to probe the contribution of two modes of cell division - symmetric vs. asymmetric - in regulating the behavior of stem cells. Neurons in the mammalian central nervous system are generated over an extended period of time during development, requiring neural stem (progenitor) cells to self-renew while generating neurons at the same time. We have postulated that neural progenitor cells balance self-renewal and differentiation during mouse neurogenesis by segregating Numb and Numbl asymmetrically to promote progenitor over neuronal fates in asymmetric divisions that produce another progenitor and a neuron. Indeed, neural progenitor cells lose their ability to self-renew in the absence of Numb and Numbl, whereas forcing them to segregate numb symmetrically inhibits neuron production by forcing their daughter cells to both choose self-renewal over differentiation. We have also identified an essential Numb and Numbl partner, ACBD3, and a novel mechanism that regulates the timing of numb activity in cell-fate specification by using the process of Golgi fragmentation and reconstitution during cell cycle to change the subcellular distribution of ACBD3. Here we seek to address how numb asymmetric localization and numb activity are regulated by combining studies using mice and Drosophila. We hypothesize that the essential regulators of numb signaling are evolutionarily conserved but differentially used in mice and Drosophila to meet their specific demands of neurogenesis. We intend to elucidate how mammalian numb proteins are asymmetrically segregated by neural progenitor cells, by first examining different Numbl protein variants for their ability to mediate asymmetric cell division during mouse neurogenesis and then identifying and characterizing the proteins binding specifically to the Numbl variant that segregates asymmetrically. Mammalian numb and ACBD3 proteins, when introduced into Drosophila, can act synergistically in a dosage-dependent manner to specify cell fates. Thus, we seek to identify novel components of the numb signaling pathway by performing a genetic screen in Drosophila to search for enhancers and suppressors of Numb-ACBD3 activity. We also seek to determine the function of the Drosophila ACBD3 homologue. Through the proposed studies, we hope to achieve a better understanding of how numb proteins specify neural progenitor fates and use the knowledge as entry points to elucidate the essential mechanisms that regulate the behavior of neural stem cells in mammals. A better understanding of how stem cells are regulated will provide novel insights for their therapeutic use to repair tissues damaged by disease, injury or aging.

描述（由申请人提供）：不对称细胞分裂，这是一个细胞分裂以产生两个不同子细胞的过程，对于在发育过程中产生细胞多样性至关重要。这种分裂也是干细胞在器官发生和维护过程中自我更新和分化的竞争需求平衡的一种有吸引力的手段，它通过产生一个留在干细胞的女儿而另一个是区分的女儿。在果蝇中，一种细胞质信号蛋白Numb不对称地将前体细胞分开并主要分离为一个子细胞。这种不对称的麻木遗传对于两个子细胞采用不同的命运至关重要。我们一直使用哺乳动物麻木的蛋白质，Numb和Numbl作为入口点，而在小鼠中的神经发生作为模型系统，以探测两种细胞分裂模式的贡献 - 对称性与非对称 - 在调节干细胞行为中的贡献。哺乳动物中枢神经系统中的神经元在发育过程中很长一段时间内产生，需要神经茎（祖细胞）细胞自我更新，同时同时产生神经元。我们假设神经祖细胞在小鼠神经发生过程中平衡了自我更新和分化，通过隔离麻木和不对称地隔离，在产生另一个祖细胞和神经元的不对称分裂中促进祖细胞而不是神经元的命运。实际上，在没有麻木和numbl的情况下，神经祖细胞失去了自我更新的能力，而迫使它们通过迫使其子细胞选择自我更新而不是差异化而迫使它们对称地隔离神经元产生。我们还鉴定了一个必不可少的麻木伴侣ACBD3，以及一种新的机制，该机制通过使用Golgi碎片和重建过程中细胞周期的过程来调节细胞命令规范中麻木活性的时机，以改变ACBD3的亚细胞分布。在这里，我们试图通过使用小鼠和果蝇结合研究来解决麻木的不对称定位和麻木活性。我们假设麻木信号的基本调节因子在进化上是保守的，但在小鼠和果蝇中有差异化，以满足其对神经发生的特定需求。我们打算通过首先检查不同的NUMBL蛋白变异物，以使其在小鼠神经发生过程中介导不对称细胞分裂，然后在蛋白质中介导并与NUMBL结合的NUMBL变体中介导非对称细胞分裂的能力，从而阐明哺乳动物麻醉蛋白如何不对称地被神经祖细胞不对称地隔离。哺乳动物麻木和ACBD3蛋白在果蝇中引入时，可以以剂量依赖性的方式协同作用以指定细胞命运。因此，我们试图通过在果蝇中执行遗传筛查来搜索Numb-ACBD3活性的增强子和抑制器，以确定麻木信号通路的新成分。我们还试图确定果蝇ACBD3同源物的功能。通过拟议的研究，我们希望更好地了解麻木蛋白如何指定神经祖细胞的命运，并以知识为入口点来阐明调节哺乳动物神经干细胞行为的基本机制。更好地了解干细胞的调节将提供新颖的见解，以用于修复因疾病，损伤或衰老而损害的组织的治疗用途。