COLLABORATIVE RESEARCH: Building the Contractile Ring in the Early Embryo

将一个细胞分裂成两个称为胞质分裂的过程是地球上所有生命的基础，该项目旨在进一步阐明以蛋白质为基础的机制的结构和功能，该机制调节细胞的分裂。完成动物细胞胞质分裂的机制被称为收缩环，它由瞬间组装的细胞骨架蛋白质带组成，产生分裂细胞所需的力。利用各种成像技术并结合计算机建模，该项目将检验这样一个假设，即在动物细胞中，收缩环由收缩蛋白的节点组装而成，这些收缩蛋白聚集成一个功能性收缩组合。该项目增加了对收缩环结构和动力学的认识，将对细胞增殖、运动、形状变化以及分化和发育领域的研究产生重大影响。该项目将培养来自四年制文科学院(迪金森学院)和为少数族裔服务的研究型大学(新墨西哥州大学)的学生，他们不仅将在各自的机构工作，还将在华盛顿大学的星期五港湾实验室(FHL)合作工作。一位在细胞骨架蛋白质动力学的基于代理的建模方面有经验的计算建模师将提供基于代理的建模的培训。最后，调查人员将开展一系列活动，通过扩大URM学生的参与、研究和教育的整合、公众参与和提高科学素养来扩大项目的影响。这个项目的目的将检验这样的假设，即收缩环由细胞骨架蛋白肌球蛋白II、肌动蛋白、七聚体和苯乙素组成的节点组装，然后组装成一个成熟的收缩机器，产生细胞质分裂所需的力量。这种基于节点的环组装模式存在于分裂酵母中，但在研究人员描述海胆胚胎早期收缩环中存在节状结构之前，从未在高级动物细胞中得到证实。以这份报告为基础，研究人员将应用超分辨率、电子和活细胞显微镜来研究海胆和海星胚胎胞质分裂过程中的节点组成、组装和聚集。利用经验数据以及现有的酵母节点会议模型，基于试剂的二维和三维模型将在Silico中进行测试，这些模拟的结果将用于进一步的实验。最后，这些方法将被应用于极叶形成的研究，它使用了在许多早期胚胎的胞质分裂期间形成的收缩环状结构，但其组成和时空调节可能与标准的收缩环有很大不同。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The process of dividing one cell into two - termed cytokinesis - is fundamental to all life on Earth and this project seeks to further elucidate the structure and function of the protein-based machinery that mediates the splitting of the cell. The machinery that accomplishes animal cell cytokinesis is known as the contractile ring and it consists of a transiently assembled belt of cytoskeletal proteins which generates the force required to divide the cell. Employing a variety of imaging technologies in combination with computational modeling, this project will test the hypothesis that in animal cells the contractile ring assembles from nodes of contractile proteins that aggregate into a functional contractile assemblage. The resulting increase in knowledge of the architecture and dynamics of the contractile ring derived from this project will have significant impacts on research in the fields of cell proliferation, movement, shape change, as well as differentiation and development. This project will train students from a four-year liberal arts college (Dickinson College) and a minority-serving research university (New Mexico State University), who will work not only at their respective institutions but also collaboratively at the University of Washington's Friday Harbor Laboratories (FHL). A computational modeler with experience in agent-based modeling of cytoskeletal protein dynamics will provide training in agent-based modeling. Lastly, the investigators will engage in a number of activities that will broaden the impact of the project through the broadening of participation of URM students, the integration of research and education, and public engagement and improvement of science literacy. The aims of this project will test the hypothesis that the contractile ring assembles from nodes comprised of the cytoskeletal proteins myosin II, actin, septins and anillin, which then congress into a mature contractile machine that generates the force necessary for cytokinesis. This node-based mode of ring assembly occurs in fission yeast, but had never been demonstrated in higher order animals cells until the investigators described the presence of node-like structures in the early contractile rings of sea urchin embryos. Using this report as a foundation, the investigators will apply super resolution, electron, and live cell microscopy to examine node composition, assembly and aggregation during cytokinesis in sea urchin and sea star embryos. Using empirical data as well as existing models for yeast node congression, two- and three-dimensional, agent-based models will be tested in silico, and results from these simulations will be used to inform further experimentation. Lastly, these approaches will be applied to the study of polar lobe formation, which uses a contractile ring-like structure that forms during cytokinesis in many early embryos, but whose composition and spatiotemporal regulation may be quite different from a standard contractile ring.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.