Abscission regulation of corticogenesis

摘要：为了使大脑发育具有适当的大小和结构，神经干细胞（NSCs）在早期 年龄必须进行增殖分裂，并保持其干细胞库扩大，但随后 在正确的时间进行神经原性分裂以产生神经元。然而， 这种命运选择从早期保持NSC，到后来选择退出细胞周期并成为一个NSC， 神经元，仍然知之甚少。细胞分裂的最后一步是分裂， 母细胞脱落发生在决定命运的时候，在顶端， 膜，许多命运信号的位置。我们开发了方法和工具来定量分析 皮质神经干细胞的体内和体外凋亡。我们发现，切割并不仅仅是切割细胞所必需的， 分开让他们活着相反，我们有了一个令人惊讶的发现， 中间体残留物（midbody residents）是发育调节的，随着发育而变化 收益。此外，我们发现，一个小脑小鼠突变体与改变的突触持续时间有一个 增殖性NSC分裂的比例降低。这些数据导致了我们的中心假设， 分裂持续时间和中间体残留持续性可以改变NSC子细胞的命运选择， 发展收益。我们将通过使用创新的遗传和细胞生物学方法来验证这一假设。 方法，单NSC部门和整个组织分析。我们将利用两种突变小鼠， 扰动消除，具体影响持续时间和中间体残留差异。我们将执行三个 具体目的：1）测试体外脱落持续时间是否与子细胞命运结局相关，2） 剖析异常的突触传递对皮质NSC子细胞命运的主要和次要影响， 形态学和谱系进展，以及3）研究在细胞内的候选信号传导机制。 顶膜，可以连接到干细胞的维护调控。的贡献 拟议的研究将增加对干细胞如何在体内发挥作用这一基本问题的理解。 发育中的组织在早期保持高增殖能力，然后在后期降低增殖能力， 子细胞类型它还将阐明NSC分裂的调节如何影响子细胞的命运， 结构，以及随后的划分。这些贡献将是重要的，因为它们将揭示新的 机制和基因通路，调节大脑的大小和结构是如何控制，并将阐明 发育过程中NSC分裂机制的特定改变如何导致大脑畸形，或 其他神经发育表型。

Abstract: In order for the brain to develop with proper size and structure, neural stem cells (NSCs) at early ages must make proliferative divisions and maintain their stemness to expand the stem cell pool, but then switch to undergo neurogenic divisions at the correct time to create neurons. However, the mechanism of this fate choice from remaining an NSC early on, to later choosing to exit the cell cycle and become a neuron, is still poorly understood. The last step of cell division is abscission, which severs the daughter from the mother cell. Abscission occurs during the time when the fate decision is made, and at the apical membrane, where many fate signals are located. We developed methods and tools to quantitatively analyze abscission in cortical NSCs, in vivo and in vitro. We found that abscission is not simply necessary to cut cells apart and keep them alive. Rather, we made the surprising discovery that both abscission duration and remnants of abscission (midbody remnants) are developmentally regulated, changing as development proceeds. Furthermore, we found that a small-brained mouse mutant with altered abscission duration has a reduced proportion of proliferative NSC divisions. These data led to our central hypothesis that changes in abscission duration and midbody remnant persistence can shift NSC daughter cells fate choices as development proceeds. We will test this hypothesis through the use of innovative genetic and cell biological approaches, on single NSC divisions and whole tissue analyses. We will utilize two mouse mutants that perturb abscission specifically, affecting duration and midbody remnants differentially. We will carry out three Specific Aims: 1) test whether abscission duration is correlated with daughter cell fate outcomes in vitro, 2) dissect the primary and secondary effects of dysregulated abscission on cortical NSC daughter cell fates, morphologies and lineage progression in vivo, and 3) investigate a candidate signaling mechanism at the apical membrane that could link abscission regulation to stem cell maintenance. The contributions of the proposed research will be to increase understanding of the fundamental question of how stem cells in developing tissues maintain high proliferative capacity early and then reduce it later in favor of differentiated daughter cell types. It will also elucidate how regulation of NSC divisions affect daughter cell fates, structures, and subsequent divisions. These contributions will be significant because they will reveal novel mechanisms and gene pathways that regulate how brain size and structure are controlled, and will elucidate how specific alterations in NSC division mechanisms during development can lead to brain malformations, or other neurodevelopment phenotypes.