Eyespot Placement and Assembly in Chlamydomonas

智力研究这项研究使用模式生物莱茵衣藻来了解复杂的分子结构是如何在细胞内的特定位置组装的。衣藻是一种单细胞、光合作用的藻类，在世界各地的淡水栖息地都有发现。衣藻细胞利用细胞前端的两根鞭毛(母鞭毛和子鞭毛)向光或远离光的方向游动，从而优化光合作用。光的强度和方向由眼点感知，这是一种复杂的结构，总是发现在细胞的外缘，细胞的前后两端之间的一半，在细胞的同一侧与子鞭毛。眼斑含有与哺乳动物眼睛中的视紫红质类似的光感受器蛋白质，以及位于眼斑特有的细胞膜或脂质颗粒中的各种其他蛋白质。这项研究将验证这样的假设，即光感受器蛋白是眼点组装和/或放置所必需的，并将识别和表征参与眼点形成的其他蛋白质。本研究得到的眼斑组装分子模型将适用于其他生物系统中各种其他亚细胞结构的研究。衣藻长期以来一直是研究光合作用和鞭毛组装的模式生物，因此这种光合作用藻类的生长、遗传操作和分子特征的条件已经建立。因此，研究衣藻眼斑是培养在亚利桑那大学攻读学位的多样化年轻科学家群体的一个极好的模式系统。许多本科生和研究生已经完成了研究眼斑组装的高级、荣誉或博士论文，亚利桑那大学的学生继续从事与眼斑相关的研究。此外，与两名小型大学教授及其学生建立的关系将继续下去。由于草绿色的衣藻细胞带有明亮的橙色眼斑和长长的鞭毛，很容易通过光学显微镜观察，参观实验室也很受小学生的欢迎。作为回应，研究人员开发了基于衣藻的生物课程，将在他们的教室里呈现给K-12学生。衣藻只是众多对光有反应的光合作用微生物中的一个。学生们对衣藻的兴趣与日俱增，因为这些微生物成为利用太阳能生产食物和燃料的重点。

INTELLECTUAL MERITThis research uses the model organism Chlamydomonas reinhardtii to understand how complex molecular structures are assembled at specific locations within a cell. Chlamydomonas is a single-celled, photosynthetic alga found in freshwater habitats throughout the world. Chlamydomonas cells optimize photosynthesis by swimming toward or away from light using two flagella (the mother flagellum and the daughter flagellum) at the anterior end of the cell. Light intensity and direction are sensed by the eyespot, a complex structure that is always found at the outer edge of the cell, half way between the anterior and posterior ends of the cell, on the same side of the cell as the daughter flagellum. The eyespot contains photoreceptor proteins that are similar to the rhodopsins in mammalian eyes, and a variety of other proteins that are located in the cell membrane layers or lipid granules that are unique to the eyespot. This research will test the hypothesis that the photoreceptor proteins are required for the assembly and/or placement of the eyespot, and will identify and characterize other proteins involved in eyespot formation. A molecular model of eyespot assembly resulting from this research will be applicable to studies of a wide variety of other sub-cellular structures in other biological systems.BROADER IMPACTSChlamydomonas has long been a model organism for the study of photosynthesis and flagellar assembly, so the conditions for growth, genetic manipulation, and molecular characterization of this photosynthetic alga are well established. Studying the Chlamydomonas eyespot is, therefore, an excellent model system for training the diverse group of young scientists pursuing degrees at the University of Arizona. A number of undergraduate and graduate students have completed their senior, honor, or Ph. D. theses studying eyespot assembly, and University of Arizona students continue to pursue eyespot-related research. Additionally, established relationships with two small college professors and their students will continue. Because the grass-green Chlamydomonas cell with its bright orange eyespot and long flagella is easily viewed through the light microscope, visiting the laboratory has also been popular with grade school students. In response, the researchers have developed Chlamydomonas-based biology lessons that will be presented to K-12 students in their classrooms. Chlamydomonas is only one of a very large number of photosynthetic microorganisms that respond to light. Student interest in Chlamydomonas is increasing as these microorganisms become the focus of efforts to produce food and fuel using energy from the sun.