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Cytoskeletal organization in apicomplexan parasites

顶端复门寄生虫的细胞骨架组织

基本信息

批准号：
6844852
负责人：
HEIDE SCHATTEN
金额：
$ 7.35万
依托单位：
UNIVERSITY OF MISSOURI-COLUMBIA
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-02-01 至 2007-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6844852
关键词：
Apicomplexa Toxoplasma gondii actins cell cycle cell nucleus centrosome cytoskeleton electron microscopy microfilaments parasitism pellicle western blottings

项目摘要

DESCRIPTION (provided by the applicant): The purpose of this research is to understand cytoskeletal organization and functions during cell division of the intracellular protozoan parasite Toxoplasma gondii, a model for harmful apicomplexan parasites that include Plasmodium falciparum and Cryptosporidium parvum. Despite the importance of the cytoskeleton for cell division in these unicellular organisms the mechanisms that power the separation of the genome remain uncertain, largely because only limited data exist about the organization and composition of the cytoskeleton. Recent data suggest an unconventional division machinery that divides the nucleus and separates the apicoplast, a single non-photosynthetic plastid that is essential for parasite survival. We hypothesize (1) that the parasite's unconventional division apparatus is based on a complex organization of microtubules, their organizing center (the centriole-centrosome complex) and perhaps other cytoskeletal components yet to be determined. Fibers of the division apparatus may associate with the pellicle (the parasite's outer membrane system) to separate the genome and the apicoplast during cell division in T. gondii; we hypothesize (2) that the centriole-centrosome complex plays an important role in the organization of the cytoskeleton and may contain proteins that differ from mammalian cells. Our specific aims are to (1) analyze the parasite's cytoskeleton during cell division with focus on the interactions with the pellicle, the apicoplast and the nucleus, and (2) to characterize the centriole-centrosome complex with focus on proteins that may differ from mammalian cells and may serve as targets to inhibit cell division in apicomplexan parasites. The novel approach of the proposed experiments is to use high-resolution field emission scanning electron microscopy (HRFESEM) on thick-sectioned resin de-embedded material. This method used in preliminary experiments allowed for the first time viewing of actin-like filaments and intermediate-like filaments which had not been possible with any other method available so far. We will further isolate the division apparatus of T. gondii and generate antibodies to determine parasite-specific centrosome proteins. This research will address unresolved questions regarding the cytoskeleton and the centriole-centrosome complex during cell division in T. gondii and, perhaps, the existence of other cytoskeletal fibers. This research will advance our understanding of cell division in apicomplexan parasites and may lead to the identification of targets to control replication of harmful apicomplexan parasites. Pilot data from this RO3 research will be used to apply for funding through the RO1 mechanism.

描述(申请人提供)：这项研究的目的是了解细胞内原生动物寄生虫弓形虫在细胞分裂过程中的细胞骨架组织和功能，弓形虫是包括恶性疟原虫和微小隐孢子虫在内的有害尖端复合体寄生虫的模型。尽管细胞骨架在这些单细胞生物体中对细胞分裂很重要，但推动基因组分离的机制仍然不确定，这主要是因为关于细胞骨架的组织和组成的数据有限。最近的数据表明，一种非传统的分裂机制将细胞核分裂并分离出质外体，这是一种对寄生虫生存至关重要的非光合体。我们假设(1)寄生虫的非常规分裂装置是基于微管及其组织中心(中心粒-中心体复合体)的复杂组织，可能还有其他尚未确定的细胞骨架成分。在弓形虫的细胞分裂过程中，分裂器的纤维可能与膜(寄生虫的外膜系统)相联系，以分离基因组和质膜；我们假设(2)中心粒-中心体复合体在细胞骨架的组织中发挥重要作用，并可能含有不同于哺乳动物细胞的蛋白质。我们的具体目标是(1)分析寄生虫在细胞分裂过程中的细胞骨架，重点是与细胞膜、质膜和细胞核的相互作用，以及(2)鉴定中心粒-中心体复合体，重点研究可能不同于哺乳动物细胞的蛋白质，并可能作为抑制顶复合体寄生虫细胞分裂的靶标。实验的新方法是使用高分辨率场发射扫描电子显微镜(HRFESEM)对厚片树脂包埋材料进行研究。在初步实验中使用的这种方法首次允许观察肌动蛋白样丝和中间体样丝，这是到目前为止任何其他可用的方法都不可能实现的。我们将进一步分离弓形虫的分裂器官，并产生抗体来确定寄生虫特异的中心体蛋白。这项研究将解决关于弓形虫细胞分裂过程中的细胞骨架和中心粒-中心体复合体以及其他细胞骨架纤维的存在的悬而未决的问题。这项研究将促进我们对顶端复合体寄生虫细胞分裂的理解，并可能导致识别控制有害顶端复合体寄生虫复制的靶标。这项R03研究的试点数据将用于通过RO1机制申请资金。