Regulation of Cell Proliferation during Plant Organ Morphogenesis

植物器官形态发生过程中细胞增殖的调控

• 批准号: 0091306
• 负责人: Keiko Torii
• 金额: $ 36万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2005-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0091306&HistoricalAwards=false
• 关键词: Regulation; Cell; Proliferation; during; Plant

0091306Torii Body size of multicellular organisms depends on the coordinated interplay of cell proliferation and differentiation of the developmental program. In higher plants, organ formation occurs throughout the life cycle by continual activity of the shoot meristem. Because plant cells lack motility due to rigid cell walls, spatio-temporal patterns of cell division and cell expansion are thought to ultimately determine plant body size. Although the cell cycle machinery that drives cell division has been extensively studied in plants, little is known about how the machinery acts in the context of growth and development of a plant as a whole. A goal of this proposal is to elucidate the connection between plant morphogenesis and cell proliferation by investigating roles of cell cycle regulators in specifying organ cell numbers, and therefore the organ size. Drs. Torii, Comai, and Roberts have identified eight Arabidopsis genes similar to the mammalian cyclin kinase inhibitor (CKI) p27kip1, which acts as a negative regulator of the cell cycle. Preliminary analyses of the Arabidopsis thaliana CKIs (AtCKI) suggested that mRNA suppression of the AtCKI causes enlargement of mature organs, presumably due to both an enlarged shoot meristem and delayed cessation of the meristematic competence of developing organs. The research in the present project period is intended to: (1) Biochemically characterize the AtCKI, (2) Analyze the relationship between cell proliferation and organogenesis by characterizing plants altered in the AtCKI levels, (3) Examine functional redundancy among different AtCKIs, and (4) Understand interplays between AtCKI-mediated cell proliferation and characterized developmental regulatory pathways. These experiments should provide a novel insight into developmental mechanism controlling plant organ size and define the roles for cell cycle control in plant organogenesis. Moreover, this research should lay the foundation for designing desirable organ sizes through genetic manipulation.

[91306 . torii]多细胞生物的体型大小取决于发育过程中细胞增殖和分化的协调相互作用。在高等植物中，器官的形成贯穿整个生命周期，通过茎分生组织的持续活动进行。由于植物细胞由于细胞壁坚硬而缺乏运动性，因此细胞分裂和细胞扩增的时空模式被认为最终决定了植物体的大小。尽管驱动细胞分裂的细胞周期机制已经在植物中得到了广泛的研究，但人们对该机制在植物整体生长发育过程中的作用知之甚少。本研究的目的是通过研究细胞周期调节因子在器官细胞数量和器官大小中的作用来阐明植物形态发生和细胞增殖之间的联系。Drs。Torii， Comai和Roberts已经确定了8个与哺乳动物周期蛋白激酶抑制剂（CKI） p27kip1相似的拟南芥基因，该基因作为细胞周期的负调节因子。对拟南芥CKIs （AtCKI）的初步分析表明，抑制AtCKI的mRNA可导致成熟器官的增大，这可能是由于茎部分生组织的增大和发育器官分生组织能力的延迟停止。本课题的研究旨在：(1)AtCKI的生化特征；(2)通过AtCKI水平改变的植物分析细胞增殖与器官发生之间的关系；(3)检查不同AtCKI之间的功能冗余；(4)了解AtCKI介导的细胞增殖与特征发育调控途径之间的相互作用。这些实验将为研究控制植物器官大小的发育机制和确定细胞周期控制在植物器官发生中的作用提供新的视角。此外，该研究为通过基因操作设计理想的器官大小奠定了基础。