Control of Organ Initiation and Size by the AINTEGUMENTA Gene

为了了解与器官起始和器官大小决定相关的调节细胞增殖的机制，人们正在研究AINTEGUMENTA(ANT)转录因子的功能。ANT是细胞增殖的重要调节因子，负责器官原基的启动和成熟器官的大小和形状的确定。1)ANT在启动所有气生侧器原基的分生组织细胞中转录，在决定器官宽度的边缘分生组织细胞中转录，在产生维管系统的分生组织原形成层细胞中转录。2)丧失功能的Ant突变表型(即没有胚珠被，花器官大小和数量减少，叶片狭窄)与细胞增殖下降有关。3)在由强35S启动子转录的转基因植物中，获得功能的表型(即增大的叶片、花器官和胚珠)与促进细胞增殖有关。因此，ANT提供了一个独特的进入信号转导通路(S)的切入点，该通路将细胞增殖的控制与器官起始以及器官大小和形状的确定联系起来。为了了解细胞增殖在器官发生过程中是如何调控的，PI将完成以下目标：1)确定器官发生过程中ANT转录模式与细胞增殖之间的关系。2)确定分生组织细胞中控制ANT转录的基因和序列。3)确定ANT转录因子的靶点，并确定它们与控制细胞增殖和器官发生的关系。4)阐明蚂蚁相互作用蛋白在控制细胞增殖和器官发生中的作用。5)通过鉴定抑制或增强弱突变等位基因ANT-3表型的突变，获得更多的器官发生调节因子。这些实验的结果将提供对控制器官启动和决定器官大小和形状的基本机制的洞察。它们将有助于阐明在器官发生过程中控制细胞增殖的信号转导途径。这些信息将产生改变作物器官大小的新方法，从而提高它们的生产力和价值。

To understand mechanisms that regulate cell proliferation associated with organ initiation and the determination of organ size, the function of the AINTEGUMENTA (ANT) transcription factor is being studied. ANT is an important regulator of cell proliferation that is responsible for organ primordia initiation and the determination of mature organ size and shape. 1) ANT is transcribed in meristematic cells that initiate all aerial lateral organ primordia, in marginal meristem cells that contribute to organ width and in meristematic procambium cells that generate the vascular system. 2) The loss-of-function ant mutant phenotype (i.e., no ovule integuments, reduction in floral organ size and number, narrow leaves) is associated with a decrease in cell proliferation. 3) In transgenic plants where ANT is transcribed from the strong 35S promoter, the gain-of-function phenotype (i.e., enlarged leaves, floral organs and ovules) is associated with increased cell proliferation. Thus, ANT provides a unique entry point into the signal transduction pathway(s) that link the control of cell proliferation with organ initiation and the determination of organ size and shape.To understand how cell proliferation is regulated during organogenesis, the PI will accomplish the following goals: 1) Determine the relationship between patterns of ANT transcription and cell proliferation during organogenesis. 2) Identify genes and sequences that control ANT transcription in meristematic cells. 3) Identify targets of the ANT transcription factor and determine their relationship to the control of cell proliferation and organogenesis. 4) Elucidate the role of an ANT interacting protein on the control of cell proliferation and organogenesis. 5) Obtain additional regulators of organogenesis by identifying mutationsthat suppress or enhance the phenotype of a weak mutant allele, ant-3. Results from these experiments will provide insight into fundamental mechanisms that control organ initiation and the determination of organ size and shape. They will help to elucidate the signal transduction pathways that control cell proliferation during organogenesis. This information will generate novel methods to modify organ size in crop plants, and thereby increase their productivity and value.