Mechanisms of Septin Assembly and Dynamics

细胞骨架是由蛋白质为基础的聚合物构成的，这是正常细胞结构和功能所必需的。这些聚合物网络作为机器和轨道来分离细胞成分，改变细胞形状，并充当蛋白质和膜支架。septin是细胞骨架中高度保守的组成部分，对细胞分裂、膜分隔和分泌等过程至关重要。从真菌到哺乳动物，septin蛋白都广泛表达。septin在细胞中聚集在一起，形成更高阶的结构，如环状、条状和纤维。我们使用一种遗传上易于处理的丝状真菌Ashbya gossypii来研究septin，因为它持久的、动态的、基于septin的大片段特别适合显微镜和生化分析。该项目的目标是解决目前尚不了解的septin架构的三个关键方面：活细胞中间隔蛋白丝聚合和连接方式的测定2. 确定哪些因素控制着septin在细胞中组装在一起；和3。septin细丝动力学的评价。该研究结合了新型单分子和偏振荧光成像，基因突变分析和体外生化方法。这个项目中的实验解决了一个一般的细胞工程问题：如何在细胞的特定位置建立持久的、动态的、恒定大小的结构。这个项目将发现细胞在空间中组织自己来执行生长和分裂等生命功能的基本规则。更广泛的影响PI致力于培养本科生和研究生，并在社区中传播科学。作为本科细胞生物学的课程主任，PI将扩展她和她的研究小组使用Ashbya作为模型系统开发的基于探究的实验室单元。在为“点击器”撰写并获得用于生物学课程的资助后，她开发了一系列问题，将基于讲座的细胞生物学课程转变为积极的学习空间，并将在未来的课程中继续扩展并与其他教师分享这个工具包。在过去的五年里，PI在实验室培养了七名本科生，其中包括两名数学和计算机科学专业的女性和一名计算机科学专业的男性。2010年夏天，一名本科生被授予REU，在伍兹霍尔海洋生物实验室与PI一起工作。今年，两名达特茅斯学院的本科生在PI的实验室完成了荣誉论文，两人的研究成果都以第一作者的身份发表。她指导了两名女博士生，一名女博士后和一名女技术员，并有五名女性轮转学生，其中两名是拉丁裔。PI在校园的许多场合谈到了女性在科学领域面临的问题，以及如何平衡科学和母亲的关系，包括各种女生联谊会的教职员工晚宴、生物学本科生协会和本科女性科学项目。PI是2010年美国细胞生物学学会年会本科生特别会议的主讲人。PI指导了两名教师学者博士后，通过与他们合作教学并每周提供教学反馈，促进他们作为教师的发展。这位PI在她所在社区的晚间研讨会上发表关于基础科学研究重要性的演讲，并在中学科学课堂上讲述了成为一名科学家的感受。PI实验室的研究生定期向当地的高中学生和教师讲授光学显微镜的原理和我们实验室的研究。PI将通过上述活动的延续，将培训、指导和当地社区参与纳入她的研究项目。

Intellectual meritThe cytoskeleton is made of protein-based polymers that are required for proper cell structure and function. These polymer networks serve as machines and tracks to segregate cell components, change cell shape, and act as protein and membrane scaffolds. The septins are a highly conserved component of the cytoskeleton important for processes such as cell division, membrane compartments, and secretion. The septin proteins are widely expressed from fungi to mammals. Septins come together in cells to build higher-order structures such as rings, bars, and fibers. We use a genetically tractable model filamentous fungus called Ashbya gossypii to study septins because its persistent, dynamic and large septin-based assemblies are especially amenable to microscopy and biochemical analysis. The objectives of this project address three key aspects of septin architecture that are presently not understood: 1. Determination of how septin filaments polymerize and link together in living cells; 2. Identification of what factors control where septins are assembled together in cells; and 3. Evaluation of the dynamics of septin filaments. The research employs a combination of novel single molecule and polarized fluorescence imaging, genetic mutant analysis and in vitro biochemical approaches. The experiments in this project tackle a general cellular engineering problem: how to erect persistent, yet dynamic, structures of a constant size at specific locations in the cell. This project will discover basic rules cells use to organize themselves in space to carry out functions of life such as growth and division. Broader ImpactsThe PI is committed to training undergraduates and graduate students and communicating science in the community. As the course director for undergraduate Cell Biology, the PI will expand on an inquiry-based lab unit developed by her and her research group using Ashbya as a model system. After writing and receiving a grant for "clickers" to use in Biology classes, she has developed a series of questions to change the lecture based cell biology class into an active learning space and will continue to expand and share this tool kit with other faculty in future offerings. The PI has trained seven undergraduates in the lab in the last five years, including two female math and computer science majors and one male computer science major. One undergraduate was awarded an REU in the summer of 2010 to work with the PI at the Marine Biological Lab in Woods Hole. Two Dartmouth undergraduates completed honors theses in the PI's lab this year and both now have had their work published as first authors. She has mentored two female PhD students, one female post-doc and one female technician and has had five female rotation students, two of whom are Latina. The PI speaks about issues facing women in science and balancing science and motherhood at many venues on campus including various sorority faculty dinners, at the Biology undergraduate society, and the undergraduate Women in Science Program. The PI was the keynote speaker at the American Society for Cell Biology Annual Meeting Special Session for undergraduate participants in 2010. The PI has mentored two teacher-scholar post-doctoral fellows to facilitate their development as teachers by co-teaching with them and providing weekly feedback on their teaching. The PI speaks at evening seminars in her community about the importance of basic science research and has spoken to middle school science classrooms about what it is like to be a scientist. Graduate students in the PI's lab regularly teach local high school students and teachers about the principles of light microscopy and the research in our lab. The PI will weave training, mentoring and local community involvement into her research program through the continuation of these described activities.