Proliferative asymmetry in the neural stem cell lineage established by asymmetric cell division

摘要 在这项拟议的工作中，我将研究神经干细胞如何建立“增殖不对称”，即 负责精确控制中枢神经系统的发育和修复。在.期间 在发育和组织修复过程中，干细胞被触发增殖。虽然扩散是必要的，但它必须是 精确地防止可能导致肿瘤发生的过度生长。随着神经干细胞的增殖，它们通常 不对称地分割。经历不对称细胞分裂的能力是神经的一个高度保守的特征 所有动物的干细胞。不对称细胞分裂产生一个保留神经干细胞的子细胞 细胞身份，以及一个子细胞，它具有神经产生祖细胞的身份。一个关键的区别 这两个子细胞之间的区别是干细胞将迅速重新进入细胞周期并再次分裂，而 祖细胞的分裂速度会慢得多，或者停止全部分裂。这种扩散的不对称性确保了 产生适当数量的神经元，而它的破坏会导致神经发生的缺陷。这个 这种增殖性不对称的分子基础大多尚不清楚。我将专注于我的独立研究项目 围绕建立这种增殖性不对称的机制。我假设这种增殖剂 不对称性是由不对称细胞中促增殖因子的差异遗传所建立的 组织。我计划学习神经干细胞如何在无脊椎动物和 脊椎动物，通过使用果蝇和斑马鱼的动物模型。研究这两种动物模型将使 Me确定神经干细胞中产生增殖不对称的保守和发散模式，而 也为我提供了新的培训机会。这两种动物模型都非常适合活体细胞成像。 在发育中的大脑中的神经干细胞。在目标1中，我将筛选极化的增殖调节因子 在母神经干细胞中。在目标2中，我将确定极化的增殖调节因子如何对 兄弟细胞之间的增殖不对称。在目标3中，我将确定PAR极性蛋白如何调节 PI3K增殖途径。通过我的初步筛选，我已经找到了一位很有前途的候选人 这似乎介导了神经干细胞谱系中的增殖不对称性，即脂质PIP3。PIP3是 由母神经干细胞在分裂前瞬间产生，然后极化到 细胞，并由保留神经干细胞身份的子细胞继承。了解PIP3如何 在不对称细胞分裂过程中建立增殖不对称的其他因素将促进我们的 了解神经干细胞如何调节发育和组织修复。通过针对性的培训活动 在提高我的赠款撰写、科学教学和指导方面的技能时，我将更好地为自己的经营做好准备 实验室。这项提议将促进科学发现和培训，这将是建立我的 独立研究计划。

ABSTRACT In the proposed work, I will be investigating how neural stem cells establish ‘proliferative asymmetries’, which are responsible for precisely controlling the development and repair of the central nervous system. During development and tissue repair, stem cells are triggered to proliferate. While proliferation is necessary, it must be precise to prevent overgrowth that can lead to tumorigenesis. As neural stem cells proliferate, they commonly divide asymmetrically. The ability to undergo asymmetric cell division is a highly conserved feature of neural stem cells across all animals. Asymmetric cell division produces one daughter cell that retains the neural stem cell identity, and one daughter cell which takes on a neuron-producing progenitor cell identity. A key difference between these two daughter cells is that the stem cell will rapidly reenter the cell cycle and divide again, while the progenitor cell will divide much more slowly or stop dividing all together. This proliferative asymmetry ensures that the proper number of neurons are produced, and its disruption leads to defects in neurogenesis. The molecular basis for this proliferative asymmetry mostly unknown. I will focus my independent research program around the mechanisms which establish this proliferative asymmetry. I hypothesize that this proliferative asymmetry is established by the differential inheritance of proliferation promoting factors during asymmetric cell division. I plan to learn how neural stem cells generate proliferative asymmetries in both invertebrates and vertebrates, through the use of Drosophila and zebrafish animal models. Studying both animal models will allow me to identify conserved and divergent modes of generating proliferative asymmetries in neural stem cells, while also providing me with new training opportunities. Both animal models are highly amenable to live cell imaging of neural stem cells in developing brains. In Aim 1, I will screening for proliferation regulators which are polarized in the mother neural stem cell. In Aim 2, I will determine how polarized proliferative regulators contribute to proliferative asymmetries between sibling cells. In Aim 3, I will determine how PAR polarity proteins regulate the PI3K proliferation pathway. Through my initial screening, I have already discovered one promising candidate that appears to mediate the proliferative asymmetry in the neural stem cell lineage, the lipid PIP3. PIP3 is transiently produced by the mother neural stem cell just before division, becomes polarized to one side of the cell, and gets inherited by the daughter cell which retains the neural stem cell identity. Discovering how PIP3 and other factors establish proliferative asymmetries during asymmetric cell division will advance our understanding of how neural stem cells mediate development and tissue repair. Through training activities aimed at improving my skills in grant writing, scientific teaching, and mentoring, I will be better prepared to run my own laboratory. The scientific discoveries and training this proposal will facilitate, will be foundational to building my independent research program.