Molecular Architecture, Function, and Biogenesis of the Ventral Disc in Giardia

描述（由申请人提供）：贾第虫是一种广泛存在的人畜共患肠道寄生虫，是人类十大寄生虫之一，可引起严重的急性和慢性腹泻病。由于缺乏协调一致的研究努力，贾第虫病已被指定为世界卫生组织（世卫组织）忽视的疾病。为了增殖和定殖小肠，滋养体首先利用鞭毛运动找到合适的附着位点，然后通过腹盘（一种独特的微管结构）附着到绒毛上来避免蠕动。腹侧椎间盘在发病机制中至关重要，因为它通过一种未确定的机制介导了与微绒毛的可逆性附着。我们的主要重点是评估腹侧盘亚结构的功能，需要整体盘构象变化，导致寄生虫附着在体内和体外。我们将首先确定鞭毛运动的贡献侧嵴（LC）接触的早期阶段的附件（目的1）。然后，我们将相关的各种光盘构象状态发生在后期附件与运动的子结构（目的2），并确定这些子结构的贡献，以产生光盘的构象附件（目的2）。最后，我们将定义的阶段光盘生物发生相对于有丝分裂后，当两个背女儿光盘组装和父母腹侧光盘拆卸，并在脱囊，当两个新的女儿光盘迅速形成的光盘子结构的组装。这项工作将为我们对椎间盘结构和功能的分析提供信息（目标1-2）。我们还将测试的作用，翻译后微管蛋白的修饰，在顺序招募光盘相关蛋白组装光盘（目的3）。影响鞭毛运动、腹盘结构、盘生物发生或盘构象动力学的药物可能直接或间接地减少滋养体在宿主中的附着，从而限制感染的起始或程度。

DESCRIPTION (provided by applicant): Giardia is a widespread zoonotic intestinal parasite and is one of the ten major parasites of humans, causing significant acute and chronic diarrheal disease. Due to the lack of concerted research efforts, giardiasis has been designated a World Health Organization (WHO) neglected disease. To proliferate and colonize the small intestine, trophozoites first find suitable sites for attachment using flagellar motility, and then avoid peristaltic flow by attaching to the villi with the ventral disc, a unique microtubule structure. Te ventral disc is critical for pathogenesis in that it mediates reversible attachment to the intestinl microvilli via an undefined mechanism. Our primary focus is to evaluate the functions of ventral disc substructures that are required for overall disc conformational changes leading to parasite attachment in vivo and in vitro. We will first determine the contributions of flagellar motility an lateral crest (LC) contact to early stages of attachment (Aim 1). We will then correlate the various disc conformational states occurring in late stage attachment with movements of substructures (Aim 2), and determine the contributions of these substructures to generating disc conformations required for attachment (Aim 2). Finally, we will define the stages disc biogenesis with respect to the assembly of disc substructures after mitosis, when two dorsal daughter discs are assembled and the parental ventral disc is disassembled, and during excystation, when two new daughter discs are rapidly formed. This work will inform our analyses of disc structure and function (Aims 1-2). We will also test the role of posttranslational tubulin modifications in sequentially recruiting disc-associated proteins to the assembling disc (Aim 3). Drugs affecting flagellar motility, ventral disc structure, disc biogenesis, or disc conformational dynamics may directly or indirectly decrease trophozoite attachment in the host, and thus limit the initiation o extent of infection.