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Anaylsis of the spatial control of cytokinesis in plants

植物胞质分裂的空间控制分析

基本信息

批准号：
6827408
负责人：
LAURIE G SMITH
金额：
$ 24.63万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
1995
资助国家：
美国
起止时间：
1995-09-01 至 2006-11-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The spatial control of cytokinesis (control of the plane of cell division) is a fundamentally important process for the development of plants as for other eukaryotes. In plant cells, a cortical preprophase band (PPB) of cytoskeletal filaments appears to be involved in establishing a "division site" in the cell cortex, to which the phragmoplast (a cytoskeletal structure that functions as the cytokinetic apparatus) is actively guided during cytokinesis. Mechanisms governing these processes are poorly understood. The overall goal of this research is to advance our understanding of the spatial control of cytokinesis in plant cells. During the previous grant period, we cloned the Tangled1 (Tan1) gene of maize and showed that it is required for proper orientation of cytoskeletal arrays involved in plant cell division. Tan1 encodes a basic protein related to the microtubule (MT)-binding basic domain of adenomatous polyposis coli (APC, a human tumor suppressor). We showed that TAN1 can bind directly to MTs in vitro, and that anti-TAN1 antibodies label MT-containing cytoskeletal structures in dividing plant cells that are misoriented in tan1 mutants (PPBs, spindles and phragmoplasts). These findings led to the hypotheses that MT-associated TAN1 protein mediates interactions of the PPB, spindle and phragmoplast with other cell components that are necessary for orienting these arrays. To establish a system for more in-depth analysis of TAN1 function, Specific Aim 1 of this proposal is to elucidate the function and expression pattern of an Arabidopsis TAN1-like gene, ATN, and the localization of its protein product. To test the hypothesis that ATN, like TAN1, helps to orient cytoskeletal arrays in dividing cells by mediating their interactions with other cell components, Specific Aim 2 is to analyze the function and localization of proteins with which ATN interacts in the yeast two-hybrid system, and their interaction with ATN in plant cells. In addition, analysis of two new discordia (dcd) mutants during the previous grant period led to the hypothesis that these genes are involved in an actin-dependent process needed for guidance of phragmoplasts to cortical division sites in asymmetrically dividing cells of the maize leaf epidermis. To test this hypothesis, Specific Aim 3 is to clone and analyze the Dcdl gene and its protein product. Insights gained from these studies will contribute to a better understanding of structural aspects of cell division that are essential for normal eukaryotic development, and the loss of which is associated with neoplastic diseases in humans and animals. In particular, this work has the potential to shed new light on the function of APC tumor suppressor protein, and thus on the treatment of human colon cancer.

描述（由申请人提供）：胞质分裂的空间控制（控制细胞分裂的平面）是一个非常重要的过程对于植物的发育和其他真核生物一样。在植物细胞中，细胞骨架丝的皮质前前期带（PPB）似乎是参与在细胞皮层中建立一个“分裂位点”，成膜体（一种细胞骨架结构，在胞质分裂期间被主动引导。管理这些问题的机制过程知之甚少。本研究的总体目标是推进我们对植物细胞胞质分裂空间控制的理解。在前期研究中，我们克隆了玉米Tangled1（Tan1）基因并表明它是细胞骨架阵列正确定向所必需的参与植物细胞分裂。Tan1编码一种碱性蛋白，大肠腺瘤性息肉病的微管（MT）结合基本结构域（APC，人肿瘤抑制因子）。我们发现TAN1可以在体外直接与MT结合，并且抗TAN 1抗体标记细胞中含有MT的细胞骨架结构在tan1突变体中错误定向的分裂植物细胞（PPBs，纺锤体和成膜体）。这些发现导致了一种假设，即MT相关的TAN1 蛋白质介导PPB，纺锤体和成膜体与其他这些元件是定向这些阵列所必需的。建立对系统TAN1的功能进行了较深入的分析，具体针对1 本研究的目的是阐明拟南芥中一个基因的功能和表达模式， TAN1样基因ATN及其蛋白产物的定位。测试假设ATN，像TAN1，有助于定向细胞骨架阵列在分裂，通过介导它们与其他细胞成分的相互作用， 2是分析ATN与蛋白质的功能和定位在酵母双杂交系统中相互作用，以及它们与ATN的相互作用，植物细胞此外，还对两个新的discordia（DCD）突变体进行了分析，上一个资助期导致了这些基因参与的假设，在一个肌动蛋白依赖的过程中，需要指导成膜细胞进入皮层，玉米叶表皮不对称分裂细胞的分裂位点。到为了验证这一假设，具体目标3是克隆和分析Dcdl基因，其蛋白质产品。从这些研究中获得的见解将有助于更好地理解细胞分裂的结构方面，正常的真核细胞发育，而这种缺失与人类和动物的肿瘤疾病。特别是，这项工作具有有可能揭示APC肿瘤抑制蛋白的功能，并因此用于治疗人类结肠癌。