Defining the mechanism of actin-mediated spindle position sensing in mouse oocytes

定义小鼠卵母细胞中肌动蛋白介导的纺锤体位置传感机制

• 批准号: 170439876
• 负责人: Dr. Jan Ellenberg
• 金额: --
• 依托单位: Europäisches Laboratorium für Molekularbiologie (EMBL)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/170439876?language=en
• 关键词: Defining; mechanism; actin; mediated; spindle

Recent work has revealed that cytoplasmic actin networks are required for the first meiotic division of oocytes at the beginning of animal life. These actin networks are responsible for transporting chromosomes over long distances and for asymmetric positioning of the meiotic spindle. Although several lines of evidence support the notion that the actin nucleators formin and Spir might be required to form these networks, we do not at all understand their molecular mechanism of action under physiological conditions. The principal aim of the present proposal is therefore to understand how Spir and formin nucleation complexes interact to nucleate actin filaments in animal oocytes, how these nucleation complexes are regulated and how the actin filaments are organized into a network to mediate chromosome/spindle positioning. To address these questions, we will take advantage of two biological model systems to study meiosis, namely starfish and mouse, because they allow us to combine genetics, biochemistry and advanced live cell imaging methods in animal oocytes. Our approach has three major complementary and integrated parts. First, we will use quantitative live cell imaging assays to characterize the function of formin and Spir in available knock out mouse models. Second, we will identify new meiotic formin/Spir accessory factors and regulators by biochemical purification and mass spectrometry in starfish. And third, we will characterize and validate these newly identified candidates under physiological conditions using both starfish and mouse oocytes. Studying the two systems will allow us to efficiently dissect the molecular mechanism underlying the formation and function of oocyte specific actin networks and reveal their evolutionarily conserved principles. Answering these questions will be of key importance for understanding the basic mechanisms of oocyte meiosis and at the same time provide one of the first physiological models to investigating the conserved Spir-formin interaction in actin filament nucleation. Both of these problems are of great interest to the field of cell biology and have important implications for human health, in particular for understanding infertility.

最近的工作表明，细胞质肌动蛋白网络是动物生命开始时卵母细胞第一次减数分裂所必需的。这些肌动蛋白网络负责染色体的长距离运输和减数分裂纺锤体的不对称定位。尽管有几条证据支持肌动蛋白核因子Forin和Spir可能是形成这些网络所必需的概念，但我们根本不了解它们在生理条件下的分子作用机制。因此，本提案的主要目的是了解Spir和Forin成核复合体如何与动物卵母细胞中有核的肌动蛋白细丝相互作用，这些成核复合体是如何调节的，以及肌动蛋白细丝是如何组织成一个网络来调节染色体/纺锤体的定位的。为了解决这些问题，我们将利用两个生物模型系统来研究减数分裂，即海星和小鼠，因为它们允许我们结合遗传学、生物化学和先进的动物卵母细胞活细胞成像方法。我们的方法有三个主要的相辅相成和综合的部分。首先，我们将使用定量活细胞成像分析来表征Forin和Spir在现有的基因敲除小鼠模型中的功能。其次，我们将通过生化纯化和质谱学鉴定新的海星减数分裂形成/Spir辅助因子和调控因子。第三，我们将在生理条件下使用海星和小鼠卵母细胞来表征和验证这些新确定的候选基因。对这两个系统的研究将使我们能够有效地剖析卵母细胞特异性肌动蛋白网络形成和功能的分子机制，并揭示它们在进化上的保守原理。回答这些问题对于理解卵母细胞减数分裂的基本机制具有重要意义，同时也为研究肌动蛋白细丝成核中保守的Spirformin相互作用提供了最早的生理模型之一。这两个问题都是细胞生物学领域非常感兴趣的问题，对人类健康，特别是对理解不孕不育有着重要的影响。