Defining the role of EDE1 a novel microtubule-located protein required for nuclear division in Arabidopsis

在许多植物中，种子的胚乳是由一系列快速的核分裂形成的，这些分裂导致一个非常大的细胞的发育，该细胞包含数百个核，称为集合体或合体。随后，细胞壁在细胞核之间发育，之后，淀粉和蛋白质(人类用于食物)被合成。重复的有丝分裂显然对胚乳的发育非常重要，但到目前为止，我们还不清楚这个过程是如何控制的。我们最近发现了一个新的拟南芥突变体，它的胚乳合体细胞核大大增大，在DNA复制后不能正确分离，我们称之为胚乳缺陷1(Ede1)。在这个新的突变体中，胚胎的发育没有受到影响。这表明该基因在胚乳中对于控制细胞周期是重要的，也就是说，细胞核是否继续分裂。我们已经从野生型拟南芥中克隆了EDE1基因，并表明它在活细胞中与微管相互作用，微管是帮助细胞分裂的脚手架结构。EDE1基因在拟南芥中有7个近亲，很可能这些近亲中至少有一些在控制植物细胞周期方面发挥了相关作用。已经发现EDE1基因在植物的其他正在经历快速细胞分裂的部分被打开，比如茎的生长尖端，这表明它可能参与控制胚乳以外的组织中的细胞周期。当EDE1蛋白与荧光报告蛋白融合并在拟南芥细胞培养中表达时，发现该蛋白与有丝分裂纺锤体有关，有丝分裂纺锤体是分离两组染色体的微管结构，进一步证明它参与了核分裂。本项目的目的是研究EDE1基因及其相关基因在细胞周期调控中的功能。我们将研究ede1突变体的细胞周期是如何改变的，以及EDE1蛋白在细胞分裂过程中如何与有丝分裂纺锤体相互作用。我们将识别与EDE1蛋白相互作用的蛋白质，以便我们能够对其在细胞中的功能有一个清晰的了解。我们还将识别相关基因突变的植物，并研究这些植物的细胞周期，帮助我们确定这些基因是否也具有控制细胞周期的相关功能。

In many plants, the endosperm of the seed forms by a series of rapid nuclear divisions that lead to the development of one very large cell containing hundreds of nuclei known as a coenocyte or syncitium. Cell walls subsequently develop between the nuclei and after that, starch and proteins (which humans use in food) are synthesised. The repeated mitosis is clearly very important to the development of the endosperm but as yet, we do not understand how the process is controlled. We have recently identified a new mutant of Arabidopsis in which the nuclei of the endosperm syncitium are greatly enlarged and do not separate correctly after DNA replication and we have called it endosperm defective 1 (ede1). In this new mutant, the development of the embryo is unaffected. This suggests the gene is important in the endosperm for controlling the cell cycle ¿ that is, whether the nuclei keep dividing or not. We have cloned the EDE1 gene from wild type Arabidopsis and shown that it interacts in living cells with microtubules, which are the scaffolding structures that help the cell divide. The EDE1 gene has seven close relatives in Arabidopsis and it is likely that at least some of these relatives play related roles in controlling the cell cycle in plants. The EDE1 gene has been found to be switched on in other parts of the plant that are undergoing rapid cell division such as the growing tip of the stem, indicating that it is likely to be involved in controlling the cell cycle in tissues other than the endosperm. When EDE1 protein is fused to a fluorescent reporter protein and expressed in cell cultures from Arabidopsis, the protein is found to associate with the mitotic spindle, which is the microtubular structure on which the two sets of chromosomes are separated, giving further evidence that it is involved in nuclear division. The aim of this project is to investigate the function of the EDE1 gene and its relatives in controlling the cell cycle. We will investigate how the cell cycle is altered in the ede1 mutant and how the EDE1 protein interacts with the mitotic spindle during cell division. We will identify proteins that interact with the EDE1 protein so that we can develop a clear picture of its function in the cell. We will also identify plants that have been mutated in the related genes and study the cell cycle in those plants, helping us to determine whether those genes also have related functions in controlling the cell cycle.