Spatial and temporal control of meiosis

减数分裂的空间和时间控制

• 批准号: RGPIN-2017-05839
• 负责人: Swan, Andrew
• 金额: $ 2.48万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711436
• 关键词: Spatial; temporal; control; meiosis

Egg activation is the process by which a mature egg is triggered to complete meiosis and at the same time to undergo critical developmental changes that prepare the egg for subsequent embryonic development. The cort gene, which encodes a meiosis-specific activator of the Anaphase Promoting Complex (APC/C), is involved in almost all aspects of egg activation. A small number of other genes have also been implicated in egg activation, including the CanB2 phosphatase and CycB3-Cdk1. A major goal of our research is to determine how these genes interact to promote the completion of meiosis. We are also interested in discovering how these cell cycle regulators also control critical developmental processes that are linked to egg activation. Aim 1. Regulation of the APC/C in Drosophila meiosis. In Aim 1 we use mass-spectrometry (MS) to identify subunits of Cort and Fzy APC/C complexes and identify post-translational modifications that change with egg activation. We will determine how CanB2 and CycB3 regulate the APC/C in meiosis by comparing MS profiles of Cort and Fzy in wild type versus mutants for these genes. To complement this biochemical approach, we employ a deficiency screen to probe the entire genome for genes that enhance or suppress cycB3 gain or loss-of-function alleles. Also in Aim 1 we will follow up on our surprising finding that Rca1, an inhibitor of APC/CFzr, has an APC/C activating role in meiosis. Aim 2. Determine how chromosomes segregate in meiosis. We found that chromosome segregation in Drosophila meiosis requires the protease, Separase, and the APC/C-mediated degradation of its inhibitor Securin. A major goal in this Aim is to identify the Separase target. Also in Aim 2 we evaluate the role of Cort, CanB2, CycB3 and Rca1 in the release of arm cohesion, and we follow up on our finding that CycB-Cdk1 plays a role in chromosome segregation in meiosis. We also determine if Separase is controlled locally in meiosis, possibly by Securin or CycB. Aim 3. Determine role of APC/CCort in sex determination. We uncovered a novel role for the APC/C in sex determination. We will test our model that APC/CCort targets a key regulator of sex determination, Tra for destruction. We propose that Cort acts in female germline to prevent maternal Tra from committing the embryo to a female fate. We propose that this role for Cort is particularly important in insect species in which Tra is the master regulator of sex determination. We will directly test this using the medfly as a model. This research program will directly train 3 PhD and 20 undergraduate students. All will receive a high level of training in a broad range of molecular, genetics, biochemistry, and biological imaging techniques. All students will be trained in scientific method, they will develop their ability to design and interpret experiments and they will learn to write and present their work. Students will be highly qualified for jobs in research, teaching and industry.

卵激活是一个成熟的卵被触发完成减数分裂，同时经历关键的发育变化，为随后的胚胎发育做准备的过程。cort基因编码减数分裂后期促进复合物（APC/C）的特异性激活剂，参与卵激活的几乎所有方面。一些其他基因也与卵子激活有关，包括CanB 2磷酸酶和CycB 3-Cdk 1。我们研究的一个主要目标是确定这些基因如何相互作用以促进减数分裂的完成。我们也有兴趣发现这些细胞周期调节因子如何控制与卵子激活相关的关键发育过程。 目标1. APC/C在果蝇减数分裂中的调控在目的1中，我们使用质谱（MS）来识别Cort和Fzy APC/C复合物的亚基，并识别随卵激活而变化的翻译后修饰。我们将确定CanB 2和CycB 3如何调节APC/C在减数分裂中通过比较Cort和Fzy在野生型与这些基因的突变体中的MS谱。为了补充这种生物化学方法，我们采用缺陷筛选来探测整个基因组中增强或抑制cycB 3获得或功能丧失等位基因的基因。同样在目标1中，我们将继续我们令人惊讶的发现，即APC/CFzr的抑制剂Rca 1在减数分裂中具有APC/C激活作用。 目标二。 确定染色体在减数分裂中是如何分离的。我们发现果蝇减数分裂中的染色体分离需要蛋白酶Separase和APC/C介导的其抑制剂Securin的降解。该目标的一个主要目标是确定分离酶目标。此外，在目标2中，我们评估的作用Cort，CanB 2，CycB 3和Rca 1的释放臂凝聚力，我们跟进我们的发现，CycB-Cdk 1在减数分裂染色体分离中发挥作用。我们还确定分离酶是否在减数分裂中受到局部控制，可能是由Securin或CycB控制。 目标3。确定APC/CCort在性别决定中的作用。我们发现了APC/C在性别决定中的新作用。我们将测试我们的模型，APC/CCort的目标是性别决定的关键调节因子，Tra的破坏。我们认为，柯特在女性生殖细胞中起作用，以防止母体Tra将胚胎交付给女性命运。我们建议，这种作用Cort是特别重要的昆虫物种中，反式脂肪酸是性别决定的主调节器。我们将使用地中海果蝇作为模型直接测试这一点。 该研究项目将直接培养3名博士生和20名本科生。所有人都将接受广泛的分子，遗传学，生物化学和生物成像技术的高水平培训。所有学生将接受科学方法的培训，他们将培养自己设计和解释实验的能力，他们将学习写作和展示自己的作品。学生将在研究，教学和工业工作的高素质。