Molecular basis of cell cycle timers and their coordination during organogenesis

细胞周期计时器的分子基础及其在器官发生过程中的协调

• 批准号: RGPIN-2019-04442
• 负责人: Sugioka, Kenji
• 金额: $ 2.19万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=683538
• 关键词: Molecular; basis; cell; cycle; timers

Most animal species begin life as a single cella fertilized egg that repeats cell divisions to form their body. In the course of cell proliferation, the orchestration of cell division timings is critical for the formation and maintenance of tissues and organs. Although activators and inhibitors of cell division are known, the molecular mechanisms that precisely specify cell division timing remains a mystery in multicellular system.*** In our body, individual cells receive different physical and chemical information. Such tissue complexity is a substantial burden for cell division studies in multicellular organisms. Indeed, multicellular studies often end up finding correlation rather than causation. To overcome this problem, we will use a unique system that will efficiently and effectively help us understand the complexity of multicellular division. Our system has four strengths first, the chosen model organism, the nematode C. elegans, has only 959 somatic cells, but is complex enough to form different tissues and organs; second, a number of genetic tools are available in C. elegans, thereby allowing us to search cell division regulators out of all ~20,000 genes of this animal; third, the timing and orientation of cell division are invariant among individual worms; this feature offers a great advantage to precisely understand the regulation of multicellular division at single-cell resolution; finally, we have recently developed a method to reconstitute and simplify the multicellular environment, using isolated embryonic cells and artificial beads, which will afford us an unprecedented advantage to understand the causal relationship between the multicellular environment and the timing of cell division. By taking advantages of our unique system, we will address the following questions:*** Q1: What are the molecular timers that specify cell division timing?*** Q2: How are cell division timings coordinated during organ formation?*** It is expected that the coordination of cell division timing is more critical in the development of functional multicellular assembly, such as organs. We will use the C. elegans intestine as a model organ. The C. elegans intestine is composed of only 20 cells originating from a single precursor cell called “E”, the descendants of which divide at different times. We will 1) precisely measure the activities of core cell division regulators in different cell types; 2) identify division timing modifiers required in specific cell types; 3) reveal a causal relationship between environmental signal and cell division timing by integrating multicellular-reconstitution assays, genetics, and live-imaging.*** Cell division regulators are remarkably similar among animals from worms to humans. Thus, our study using C. elegans should uncover the critical mechanisms that orchestrate multicellular division and animal development.

大多数动物物种的生命始于一个单一的细胞，受精卵重复细胞分裂形成自己的身体。在细胞增殖过程中，细胞分裂时序的编排对组织器官的形成和维持至关重要。尽管细胞分裂的激活剂和抑制物已知，但在多细胞系统中，精确指定细胞分裂时间的分子机制仍然是一个谜。*在我们的体内，单个细胞接收不同的物理和化学信息。这种组织复杂性对多细胞生物体的细胞分裂研究来说是一个沉重的负担。事实上，多细胞研究最终发现的往往是相关性而非因果关系。为了克服这个问题，我们将使用一种独特的系统，该系统将有效地帮助我们了解多细胞分裂的复杂性。我们的系统有四个优点：第一，所选择的模式生物线虫只有959个体细胞，但足够复杂，可以形成不同的组织和器官；第二，线虫中有许多遗传工具，从而使我们能够从这种动物的全部20,000个基因中寻找细胞分裂调节因子；第三，细胞分裂的时间和方向在单个蠕虫中是不变的；这一特征为在单细胞分辨率下准确理解多细胞分裂的调节提供了极大的优势；最后，我们最近开发了一种方法来重建和简化多细胞环境，使用分离的胚胎细胞和人造珠子，这将为我们理解多细胞环境和细胞分裂时间之间的因果关系提供前所未有的优势。通过利用我们独特的系统，我们将解决以下问题：*Q1：决定细胞分裂时机的分子计时器是什么？*Q2：细胞分裂时机在器官形成过程中是如何协调的？*预计细胞分裂时机的协调在器官等功能多细胞组装的发展中更加关键。我们将使用线虫的肠道作为模型器官。线虫的肠道只由20个细胞组成，这些细胞起源于一个名为“E”的前体细胞，其后代在不同的时间分裂。我们将1)精确测量不同细胞类型中核心细胞分裂调控因子的活性；2)确定特定细胞类型所需的分裂调控因子；3)通过整合多细胞重组分析、遗传学和活体成像来揭示环境信号与细胞分裂调控之间的因果关系。*细胞分裂调控因子在从蠕虫到人类的动物中都非常相似。因此，我们对线虫的研究应该揭示协调多细胞分裂和动物发育的关键机制。