Flagellar Motility and Assemlby

描述(申请人提供)：这项研究的长期目标是了解纤毛和鞭毛的结构、组装和功能，以及它们在人类健康中的作用。这些研究利用衣藻和老鼠作为模式生物，重点研究在纤毛生物中高度保守的过程和蛋白质。将采取遗传学、生物化学和细胞生物学相结合的方法。其中一个正在研究的过程是鞭毛内转运(IFT)，这是几乎所有纤毛和鞭毛组装和维持所必需的。IFT涉及粒子向鞭毛尖端和背部的运动。这些粒子包含至少16个不同的亚基，但对单个亚基的功能几乎一无所知。研究将对两种高度保守的IFT颗粒蛋白IFT46和IFT20缺失的衣藻突变株进行鉴定，以检验IFT46参与外动力蛋白臂向鞭毛运输的假设，以及IFT20参与向鞭毛运送膜蛋白的假设。另一个正在研究的过程是纤毛和鞭毛运动的机制。最近参与这一过程的一种蛋白质是海鞘蛋白，它是衣藻鞭毛轴丝中微管中心对(CP)的一种成分。Hydin似乎在控制动力蛋白手臂活动的CP/放射状辐条信号通路中发挥作用。将进行实验，以确定在CP和放射状辐条中与海绵体相互作用的蛋白质。在小鼠和可能的人类中，Hydin缺陷会导致脑积水，这是脑脊液在脑室中的致命积聚。研究将使用Hydin缺陷小鼠来确定Hydin是否也是哺乳动物的CP蛋白，以及它对大脑和呼吸道的纤毛运动是否重要。在相关研究中，将对衣藻CP蛋白进行全球分析，以填补我们对这一重要结构的了解的一个很大空白，并促进对海绵蛋白和CP/径向辐条相互作用的研究。另一种正在研究的重要疾病蛋白是肾囊藻毒素-4。在人类中，肾囊藻毒素-4的缺陷会导致囊性肾病和视网膜退化。它被认为是纤毛过渡区的一种蛋白质，但对其功能一无所知。缺乏肾囊藻蛋白-4的衣藻突变株将被鉴定，以更多地了解该蛋白在过渡区的特定位置和功能。被研究的过程和蛋白质中的缺陷会在人类和脊椎动物模式生物中引起疾病。这项研究将提供有关纤毛和鞭毛在囊性肾疾病、视网膜变性、原发纤毛运动障碍、男性不育和脑积水中的作用的新信息。

DESCRIPTION (provided by applicant): The long-term goals of this research are to understand the structure, assembly, and function of cilia and flagella, and their roles in human health. The studies are utilizing Chlamydomonas and mice as model organisms, and are focused on processes and proteins that are highly conserved among ciliated organisms. A combination of genetic, biochemical and cell biological approaches will be taken. One process under investigation is intraflagellar transport (IFT), which is necessary for the assembly and maintenance of almost all cilia and flagella. I FT involves the movement of particles to the tip of the flagellum and back. These particles contain at least 16 different subunits, but almost nothing is known about the functions of the individual subunits. Studies will characterize Chlamydomonas null mutants defective in two highly conserved IFT-particle proteins, IFT46 and IFT20, to test the hypotheses that IFT46 is involved in transport of the outer dynein arms into the flagellum, and that IFT20 is involved in delivery of membrane proteins to the flagellum. Another process being studied is the mechanism of ciliary and flagellar movement. One protein recently implicated in this process is hydin, a component of the central pair (CP) of microtubules in the Chlamydomonas flagellar axoneme. Hydin appears to have a role in the CP/radial spoke signaling pathway that controls dynein arm activity. Experiments will be carried out to identify the proteins with which hydin interacts in both the CP and the radial spokes. In the mouse and possibly in humans, Hydin defects cause hydrocephalus, which is the lethal accumulation of cerebrospinal fluid in the ventricles of the brain. Studies will use mice defective in Hydin to determine if Hydin also is a CP protein in mammals, and if it is important for ciliary motility in the brain and airway. In related studies, a global analysis of Chlamydomonas CP proteins will be carried out to fill a large gap in our knowldedge of this important structure, and to facilitate studies of hydin and of CP/radial spoke interaction. Another important disease protein being investigated is nephrocystin-4. Defects in Nephrocystin-4 cause cystic kidney disease and retinal degeneration in humans. It is believed to be a protein of the ciliary transition region, but nothing is known about its function. A Chlamydomonas mutant lacking nephrocystin-4 will be characterized to learn more about this protein's specific location and function in the transition region. Defects in the processes and proteins under investigation cause disease in humans and vertebrate model organisms. The research will provide new information on the role of cilia and flagella in cystic kidney disease, retinal degeneration, primary ciliary dyskinesia, male infertility, and hydrocephalus.