POWRE: Eyespot Assembly in Chlamydomonas

该项目是一个研究的组装和组织的眼点的单细胞的昆虫，衣原体。眼斑是一种感光细胞器，通过控制该生物体所具有的鞭毛而产生特征性的趋光行为。 眼点的几个特点使它成为一个非常有趣的系统。 它包括质膜和叶绿体的一部分下层紧密贴壁的膜的成分。 与叶绿体膜的这一区域相关联的是类胡萝卜素色素颗粒层，其将光反射到质膜的并置的视紫红质感光区域。 视紫红质的光激活导致钙门控进入细胞，这启动了信号转导途径，该途径在模式化鞭毛运动中达到高潮，以使生物体朝向或远离光源移动。 钙通道尚未被表征，实际上可能是衣原体视紫红质。 同样令人着迷的是，相对于鞭毛复杂的小根结构，眼点精确地定位在细胞表面。 在细胞分裂过程中，眼点首先消失。然后形成两个新的眼点，每个眼点与分割平面成90度，彼此成180度。 该系统提出了许多有趣的问题，即如何调节单个组件的表达，以及这些组件如何组装成高度有序的功能结构。在这次休假研究中，将追求三个具体目标。 目的是（1）使用生物物理技术来分析眼点组装突变体的生理和行为，（2）分析多眼突变体，这些突变体可能在细胞分裂期间的眼点组装定位系统中存在缺陷，以及（3）使用免疫荧光光学显微镜，绿色荧光蛋白蛋白质技术和免疫电子显微镜，以确定正常和变异生物 这是一个POWRE项目，将大大提高科学培训和调查人员的专业知识。

The project is a study of the assembly and organization of the eyespot of the unicellular alga, Chlamydomonas. The eyespot is a light-sensing organelle which gives rise to characteristic phototactic behavior through control of the flagella which this organism has. Several features of the eyespot make it an extremely interesting system. It includes components of both the plasma membrane and a portion of the underlying, closely apposed membranes of the chloroplast. Associated with this region of the chloroplast membranes are layers of carotenoid pigment granules which reflect light to the apposed rhodopsin light-sensing region of the plasma membrane. Light activation of the rhodopsin leads to gated entry into the cell of calcium which initiates a signal transduction pathway that culminates in patterned flagellar movements to move the organism toward or away from the light source. The calcium channel has not been characterized and may in fact be the Chlamydomonas rhodopsin. Also fascinating is the fact that the eyespot is precisely positioned on the surface of the cell with respect to the complex rootlet structures of the flagella. During cell division, the eyespot first disappears. Then two new eyespots form, each 90 degrees from the division plane and 180 degrees from each other. The system poses numerous interesting questions of how expression of individual components is regulated and how these components are assembled into the highly ordered, functional structures. In this sabbatical study, three specific aims will be pursued. The aims are (1) to use biophysical techniques to analyze the physiology and behavior of eyespot-assembly mutants, (2) to analyze multi-eye mutants which presumably have defects in the positioning system for eyespot assembly during cell division, and (3) to use immunofluorescence light microscopy, GFP-protein techniques and immunoelectron microscopy to determine the organization of some of the major components in the eyespot structure of both normal and mutant organisms. This is a POWRE project which will significantly enhance the scientific training and expertise of the investigator.