Function of the Nuclear Ran/RCCI Regulatory System in Plants

核 Ran/RCCI 调节系统在植物中的功能

• 批准号: 9506985
• 负责人: Wilhelm Gruissem
• 金额: $ 27.8万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-01 至 1998-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9506985&HistoricalAwards=false
• 关键词: Function; Nuclear; Ran; RCCI; Regulatory

9506985 Gruissem Cells regulate their growth by controlling their progression into the cell cycle, but the molecular mechanisms for these controls are not well understood. It has been shown that the nuclear Ras-like GTP-binding protein Ran and its nucleotide exchange factor RCC1 form a complex that is critical for a number of nuclear functions, including entry into and progression of DNA replication, and entry into cell division. Mutations in either Ran or RCC1 have complex phenotypes in animal and yeast cells and affect many processes, including DNA synthesis and gene expression, often resulting in cell death. This project is an investigation of the functions of Ran and RCC1 in plant cell division and sexual reproduction. The proposed studies of the Ran/RCC1 regulatory complex in a multicellular system that is amenable to in vivo manipulations should reveal novel and as yet poorly understood functions for these conserved proteins. Preliminary data indicate that plant Ran is a highly conserved nuclear protein which can suppress a fission yeast cell cycle mutation. Ran is encoded by a family of genes in tomato whose members are differentially expressed. The function of Ran and RCC1 in tomato plants will be investigated using transgenic tomato plants expressing mutant Ran proteins in an inducible fashion. This is a novel and powerful tool to investigate the role of these proteins in development. In addition, the subcellular distribution and function of the proteins during cell division and sexual reproduction are not understood. Plant cells present a useful genetic system for such functional and localization studies. Together, these experiments establish an important basis for studies to understand the function of the Ran/RCC1 regulatory complex in a signal transduction network that regulates the integration of cell growth and cell division %%% During entry into any phase of the cell cycle, there are complex and diverse functions which must be coor dinated. The phase which leads to initiation of mitosis, the M phase of the cell cyle, requires, and to some degree may be driven by, multiple activities, some of which involve the Ran gene product and its associated RCC1 gene product. However, the work to date on these genes has been done primarily in yeast and mammalian systems. This work pulls together the suggestive previous work done in yeast and mammalian cell tissue culture and provides a means to determine definitive functions of this gene complex through the use of transgenic technologies in tomato and Arabidopsis plants. Work has already shown that the genes for Ran/RCC1 in plants are very similar to those found in yeast and mammals. The work also shows that the plant genes can functionally replace non-functional genes in yeast. Ending these studies to plants takes advantage of the multiple known plant mutations in meiosis, the "reduction" division which gives rise to sexual gametes. The commonality between the early phases of mitosis and meiosis would indicate that the definitive role for these proteins might be uncovered by exploiting advanced knowledge in this area of plant biology. Extending the work to plants also takes advantage of the "naturally" occuring cell cycle arrest points and activity in a mature, differentiated higher plant. Discovery of the role of the Ran/RCC1 regulatory complex in the signal transduction network involved in the normal development of plants should provide a deeper of understanding of how these very basic, common signaling mechanisms are coordinated during plant, animal and fungal growth. ***

9506985 Gruissem 细胞通过控制其进入细胞周期的进程来调节其生长，但这些控制的分子机制尚不清楚。 研究表明，核 Ras 样 GTP 结合蛋白 Ran 及其核苷酸交换因子 RCC1 形成复合物，该复合物对于许多核功能至关重要，包括 DNA 复制的进入和进展以及细胞分裂。 Ran 或 RCC1 的突变在动物和酵母细胞中具有复杂的表型，影响许多过程，包括 DNA 合成和基因表达，通常导致细胞死亡。 该项目旨在研究 Ran 和 RCC1 在植物细胞分裂和有性生殖中的功能。 拟对多细胞系统中的 Ran/RCC1 调节复合物进行体内操作的研究应该揭示这些保守蛋白的新颖且迄今知之甚少的功能。 初步数据表明，植物Ran是一种高度保守的核蛋白，可以抑制裂殖酵母细胞周期突变。 Ran 由番茄中的一个基因家族编码，该家族的成员表达差异。 将使用以诱导方式表达突变 Ran 蛋白的转基因番茄植物来研究 Ran 和 RCC1 在番茄植物中的功能。 这是研究这些蛋白质在发育中的作用的一种新颖而强大的工具。 此外，细胞分裂和有性生殖过程中蛋白质的亚细胞分布和功能尚不清楚。 植物细胞为此类功能和定位研究提供了有用的遗传系统。 总之，这些实验为了解 Ran/RCC1 调节复合物在信号转导网络中的功能奠定了重要基础，该网络调节细胞生长和细胞分裂的整合%%% 在进入细胞周期的任何阶段期间，都存在必须协调的复杂多样的功能。导致有丝分裂起始的阶段，即细胞周期的 M 期，需要多种活动，并且在某种程度上可能由多种活动驱动，其中一些活动涉及 Ran 基因产物及其相关的 RCC1 基因产物。然而，迄今为止对这些基因的研究主要是在酵母和哺乳动物系统中完成的。 这项工作汇集了先前在酵母和哺乳动物细胞组织培养中所做的暗示性工作，并提供了一种通过在番茄和拟南芥植物中使用转基因技术来确定该基因复合物的确定功能的方法。 研究已经表明，植物中的 Ran/RCC1 基因与酵母和哺乳动物中发现的基因非常相似。 这项工作还表明，植物基因可以在功能上替代酵母中的非功能基因。 结束对植物的这些研究利用了减数分裂中多种已知的植物突变，减数分裂是产生性配子的“减少”分裂。 有丝分裂和减数分裂早期阶段之间的共性表明，通过利用植物生物学这一领域的先进知识，可以揭示这些蛋白质的决定性作用。 将这项工作扩展到植物还利用了成熟、分化的高等植物中“自然”发生的细胞周期停滞点和活性。 Ran/RCC1 调控复合物在植物正常发育涉及的信号转导网络中的作用的发现，应该可以让我们更深入地了解这些非常基本、常见的信号机制在植物、动物和真菌生长过程中如何协调。 ***