Function of the Arabidopsis Gene TORMOZ in Cell Division and Development

控制细胞分裂是多细胞生物体发育的一个重要特征。在高等植物中，细胞分裂的时机和平面都受到调节，并对发育线索做出反应。尽管有广泛的研究表明，细胞骨架在执行在预定平面上分裂的决定中起着重要作用，但关于其潜在的分子机制的信息很少。在拟南芥中发现了一种名为tormoz(Toz)的突变，在该突变中，胚胎的纵向分裂是随机的。突变的胚胎会停止发育，但可以被挽救，以产生具有严重形态缺陷的幼苗。预测的toz基因产物似乎在从酵母到人类的每一种已测序的真核生物中都有密切的同源性。然而，TOZ相关蛋白的功能在任何物种中都没有被研究过。将研究toz基因产物在拟南芥细胞分裂和发育中的作用。首先，toz突变幼苗将被用来检查突变对植物发育的影响，包括细胞分裂平面缺陷对图案形成和细胞规格的影响程度。其次，将对toz突变细胞进行研究，以确定toz在植物有丝分裂和胞质分裂的细胞骨架组织中的可能功能。第三，将研究toz基因产物在拟南芥细胞分裂过程中的细胞内定位，以提供其可能参与控制分裂平面的机制的线索。第四，我们将试图确定TOZ蛋白可能的相互作用伙伴，以获得关于TOZ蛋白执行其功能的分子机制的进一步信息。这些研究将有助于理解植物发育中细胞分裂的控制，并可能增加对动物和真菌细胞分裂的了解。该项目包括对学生和博士后研究员的培训以及少数群体的参与。

0235548SundaresanThe control of cell division is an important feature of development in multicellular organisms. In higher plants, both the timing and the plane of cell division are regulated and responsive to developmental cues. Although there are extensive studies showing that the cytoskeleton is important in executing the decision to divide in a predetermined plane, there is little information on the underlying molecular mechanisms. A mutation in Arabidopsis called tormoz (toz) has been identified, in which longitudinal divisions of the embryo are randomized. The mutant embryos arrest but can be rescued to generate seedlings which have severe morphological defects. The predicted TOZ gene product appears to have a close homolog in every sequenced eukaryote from yeast to humans. However, the function of the TOZ-related proteins has not been previously studied in any species. The role of the TOZ gene product in cell division and development in Arabidopsis will be investigated. First, the toz mutant seedlings will be used to examine how plant development has been affected by the mutation, including the extent to which patterning, and cell specification have been perturbed by the defect in cell division planes. Second, studies of toz mutant cells will be undertaken to determine possible functions of TOZ in the organization of the plant cytoskeleton for mitosis and cytokinesis. Third, the intracellular localization of the TOZ gene product during cell division in Arabidopsis will be studied to generate clues to the mechanism by which it may be involved in the control of division plane. Fourth, we will attempt to identify putative interacting partners of TOZ in order to gain further information on the molecular mechanism by which the TOZ protein executes its function. These studies will help to understand the control of cell division in plant development, and may add to the knowledge of cell division in animals and fungi. The project includes training of students and postdoctoral fellows and minority participation.